Method and apparatus for sending and receiving signaling in wireless local area network

ABSTRACT

A method includes generating, by an access point (AP), signaling that includes an AP identifier (ID) field, a bandwidth (BW) field, a guard interval (GI) field, a cyclic redundancy check (CRC) field, and a tail field, the AP ID field is used to indicate an ID of the AP, the BW field is used to indicate bandwidth required for data transmission subsequent to the signaling, the GI is used to indicate a length of a cyclic prefix (CP) required for data transmission subsequent to the signaling, the CRC field is used to guard a field before the CRC field in the signaling, and the Tail field is used to empty an encoder and a decoder, where the CRC field and the Tail field are the last two fields of the signaling. The method also includes sending, by the AP, the signaling.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/492,053, filed on Apr. 20, 2017, which is a continuation ofInternational Application No. PCT/CN2015/070252, filed on Jan. 7, 2015,which claims priority to International Patent Application No.PCT/CN2014/088972, filed on Oct. 20, 2014, and International ApplicationNo. PCT/CN2014/093183, filed on Dec. 5, 2014. All of the afore-mentionedpatent applications are hereby incorporated by reference in theirentireties.

TECHNICAL FIELD

The present embodiments relate to the communications field, and inparticular, to a method and an apparatus for sending and receivingsignaling in a wireless local area network.

BACKGROUND

A wireless local area network (WLAN for short) is a network system inwhich data is transmitted over the air by using a radio frequencytechnology. With wide application of an intelligent terminal, peoplehave ever-increasing demands for network data traffic, and using theWLAN to bear the traffic has become one of very important manners oftransmitting information and data.

For development of a WLAN technology, a standard of the WLAN technologyneeds to be formulated, popularized, and applied. Institute ofElectrical and Electronics Engineers (IEEE for short) 802.11 series aremain standards of the WLAN, and go through several generations ofmainstream standards such as 802.11, 802.11b/g/a, 802.11n, and 802.11ac.

The WLAN technology is based on a computer network and wirelesscommunications technology, and in a computer network structure, alogical link control (LLC for short) layer and an application layerabove the LLC layer may have a same or different requirements fordifferent physical layers (PHY for short). Therefore, a WLAN standard ismainly for the physical layer and a Media Access Control (MAC for short)layer, and relates to a used technical specification and technicalstandard, such as a radio frequency range and an air interfacecommunications protocol.

A physical layer frame in the WLAN standard may also be referred to as aphysical layer convergence procedure (PLCP for short) protocol data unit(PPDU for short), and includes a PLCP header and a PLCP service dataunit (PSDU for short). The PLCP header mainly includes a training fieldand a signaling (SIG for short) field.

Currently, the 802.11ax that is being researched and formulatedcontinues evolving the WLAN technology. In the 802.11ax standard,orthogonal frequency division multiple access (OFDMA for short) is usedto improve transmission efficiency. However, there is no OFDMA-baseddesign solution for common signaling in the WLAN system at present.

SUMMARY

Embodiments of the present invention provide a method and an apparatusfor sending and receiving signaling in a wireless local area network(WLAN), so as to resolve a prior-art problem that there is no orthogonalfrequency division multiple access (OFDMA)-based design solution forcommon signaling in a WLAN system.

To achieve the foregoing objective, the embodiments of the presentinvention provide the following solutions.

A first aspect of the disclosure provides a method for sending signalingin a wireless local area network WLAN, where the method includes:generating, by an access point (AP), signaling, where the signalingincludes a single-user (SU)/multi-user (MU) field, the SU/MU field isused to indicate whether scheduling transmission is single-usertransmission or multi-user transmission. The method also includes if theSU/MU field indicates that this scheduling transmission is single-usertransmission, the signaling does not include a high efficiency Wi-FiSignaling Field 2 (HEW-SIG2) that includes resource indicationinformation. Additionally, the method includes sending, by the AP, thesignaling.

A second aspect of the disclosure provides a method for receivingsignaling in a wireless local area network WLAN, where the methodincludes receiving, by a station, signaling, where the signalingincludes a SU/MU field, the SU/MU field is used to indicate whetherscheduling transmission is single-user transmission or multi-usertransmission. The method also includes if the SU/MU field indicates thatthis scheduling transmission is single-user transmission, the signalingdoes not include a HEW-SIG2 that includes resource indicationinformation. Additionally, the method includes receiving or sending, bythe station, data according to the received signaling.

A third aspect of the disclosure provides an apparatus for sendingsignaling in a wireless local area network WLAN, where the apparatusincludes: a first module, configured to generate, a signaling, where thesignaling includes a SU/MU field, the SU/MU field is used to indicatewhether scheduling transmission is single-user transmission ormulti-user transmission; and if the SU/MU field indicates that thisscheduling transmission is single-user transmission, the signaling doesnot include a HEW-SIG2 that includes resource indication information; asecond module, configured to send, the signaling.

A fourth aspect of the disclosure provides an apparatus for receivingsignaling in a wireless local area network WLAN, where the apparatusincludes: a first module, configured to receive a signaling, where thesignaling includes a SU/MU field, the SU/MU field is used to indicatewhether scheduling transmission is single-user transmission ormulti-user transmission; and if the SU/MU field indicates that thisscheduling transmission is single-user transmission, the signaling doesnot include a HEW-SIG2 that includes resource indication information; asecond module, configured to receive or send data according to thereceived signaling.

The embodiments of the present invention provide a method and anapparatus for sending and receiving signaling in a WLAN, and the methodincludes: generating, by an AP, signaling, where the signaling includesan AP identifier (ID) field, a bandwidth (BW) field, a guard interval(GI) field, a cyclic redundancy check (CRC) field, and a Tail field, theAP identifier (ID) field is used to indicate an ID of the AP, the BWfield is used to indicate bandwidth required for data transmissionsubsequent to the signaling, the GI field is used to indicate a lengthof a CP required for data transmission subsequent to the signaling, theCRC field is used to guard a field before the CRC field in thesignaling, and the Tail field is used to empty an encoder and a decoder,where the CRC field and the Tail field are the last two fields of thesignaling; and sending, by the AP, the signaling. The foregoing solutionprovides an OFDMA-based design solution for common signaling in a WLANsystem, thereby resolving a prior-art problem that there is noOFDMA-based design solution for common signaling in the WLAN system.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention more clearly, the following briefly describes the accompanyingdrawings required for describing the embodiments or the prior art.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present invention, and persons ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a physical layer framestipulated in the 802.11a standard;

FIG. 2 is a schematic structural diagram of a signaling field in the802.11a;

FIG. 3 is a schematic structural diagram of a physical layer frame in amixed format stipulated in the 802.11n standard;

FIG. 4 is a schematic structural diagram of a signaling field in the802.11a;

FIG. 5 is a schematic structural diagram of a physical layer framestipulated in the 802.11ac standard;

FIG. 6 is a schematic structural diagram of a signaling field in the802.11ac;

FIG. 7 is a schematic diagram of a network architecture of a wirelesslocal area network (WLAN) according to an embodiment of the presentinvention;

FIG. 8 is a schematic flowchart of a method for sending signaling in aWLAN according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a location of high efficiency Wi-FiSignaling Field 1 (HEW-SIG1) in a data frame according to an embodimentof the present invention;

FIG. 9a is a schematic structural diagram of a data frame according toan embodiment of the present invention;

FIG. 10 is a schematic structural diagram 1 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 11 is a schematic structural diagram 2 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 12 is a schematic structural diagram 3 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 13 is a schematic structural diagram 4 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 14 is a schematic structural diagram 5 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 15 is a schematic diagram of an uplink frame structure formataccording to an embodiment of the present invention;

FIG. 16 is a schematic diagram of a downlink frame structure formataccording to an embodiment of the present invention;

FIG. 17 is a schematic diagram of a frame structure format cascadingdownlink and uplink according to an embodiment of the present invention;

FIG. 18 is a schematic flowchart of a method for receiving signaling ina WLAN according to an embodiment of the present invention;

FIG. 19A and FIG. 19B are a schematic flowchart of parsing signalingHEW-SIG1 according to an embodiment of the present invention;

FIG. 20 is a schematic diagram of a location of a transition time pointaccording to an embodiment of the present invention;

FIG. 21 is a schematic diagram of a time domain location of an uplinktransmission resource according to an embodiment of the presentinvention;

FIG. 22 is a schematic structural diagram 1 of an access point (AP)according to an embodiment of the present invention;

FIG. 23 is a schematic structural diagram 2 of an AP according to anembodiment of the present invention;

FIG. 24 is a schematic structural diagram 1 of a station (STA) accordingto an embodiment of the present invention;

FIG. 25 is a schematic structural diagram 2 of a STA according to anembodiment of the present invention;

FIG. 26 is a schematic structural diagram 3 of an AP according to anembodiment of the present invention;

FIG. 27 is a schematic structural diagram 4 of an AP according to anembodiment of the present invention;

FIG. 28 is a schematic structural diagram 3 of a STA according to anembodiment of the present invention;

FIG. 29 is a schematic structural diagram 4 of a STA according to anembodiment of the present invention;

FIG. 30 is a schematic flowchart of a method for sending signaling in aWLAN according to an embodiment of the present invention;

FIG. 31 is a schematic structural diagram 6 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 32 is a schematic flowchart of a method for sending signaling in aWLAN according to an embodiment of the present invention;

FIG. 33A and FIG. 33B are a schematic flowchart of parsing signalingHEW-SIG1 according to an embodiment of the present invention;

FIG. 34 is a schematic flowchart of a method for sending signaling in aWLAN according to an embodiment of the present invention;

FIG. 35 is a schematic structural diagram 7 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 36 is a schematic structural diagram 8 of HEW-SIG1 according to anembodiment of the present invention;

FIG. 37 is a schematic flowchart of a method for sending signaling in aWLAN according to an embodiment of the present invention;

FIG. 38 is a schematic structural diagram 5 of a STA according to anembodiment of the present invention;

FIG. 39 is a schematic structural diagram 5 of an AP according to anembodiment of the present invention;

FIG. 40a to FIG. 40m are schematic structural diagrams of HE-SIG-A orHE-SIG-B according to an embodiment of the present invention;

FIG. 41 is a schematic diagram of a processing procedure of a receiveend according to an embodiment of the present invention; and

FIG. 42 is another schematic diagram of a processing procedure of areceive end according to an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Physical layer frame structures in three generations of typical WLANstandards 802.11a, 802.11n, and 802.11ac are briefly described asfollows.

FIG. 1 is a schematic structural diagram of a physical layer framestipulated in the 802.11a standard. A physical layer convergenceprocedure (PLCP) header includes a short training field (STF for short),a long training field (LTF for short), and a signaling (SIG) field. ThePLCP header part may also be referred to as a preamble part. The STF isused for data packet detection, automatic gain control (AGC) setting,initial frequency offset estimation, and initial time synchronization.The LTF is located after the STF and is used for channel estimation, andmore accurate frequency offset estimation and initial timesynchronization. The SIG field is located after the LTF, and includes anorthogonal frequency division multiplexing (OFDM for short) symbol thatis used to identify a rate and length information of the data packet.

The SIG field in the 802.11a standard includes a single element of 4 μs(an OFDM element of 3.2 μs and a cyclic prefix (CP for short) of 0.8μs). A waveform of the SIG field includes 64 subcarriers, and a locationrange of the subcarriers of the SIG field is −32, −31, . . . , −1, 0, 1,. . . , 31. Subcarriers that carry signals are located in −26, −25, . .. , −2, −1, 1, 2, . . . , 25, 26, where pilot subcarriers are located in−21, −7, 7, 21, and remaining 48 subcarriers carry encoded SIG bits. Therest subcarriers that are located in −32, . . . , −27, 27, . . . , 31are guard subcarriers, and 0 is a direct current subcarrier. The SIGfield is transmitted by means of binary phase shift keying (BPSK forshort) modulation and half-rate binary convolutional coding; therefore,as shown in FIG. 2, the SIG includes 24 information bits. Bits 0 to 3are rate bits and are used to indicate a modulation and coding scheme(MCS for short) used in data part transmission, bit 4 is a reservationbit, and bits 5 to 16 are length bits and are used to indicate a lengthof data or an amount of data. Bit 5 is a least significant bit (LSB forshort), and bit 16 is a most significant bit (MSB for short). Bit 17 isa check bit and is used to perform even parity check on the first 17bits. Because binary convolutional coding is separately performed on theSIG and the following data part, 6 bits of a tail are set to 0, to emptyan encoder and a decoder.

FIG. 3 is a schematic structural diagram of a physical layer frame in amixed format stipulated in the 802.11n standard. A PLCP header in amixed format in the 802.11n includes two parts: a legacy PLCP header anda PLCP header in the 802.11n. The legacy (L for short) herein mainlyrefers to a PLCP header part in the 802.11a. High throughput (HT forshort) herein mainly refers to the PLCP header part in the 802.11n. Toensure backward compatibility, an L-STF in the L-Preamble part is thesame as an STF field in a preamble in the 802.11a, an L-LTF field is thesame as an LTF field in the preamble in the 802.11a, and an L-SIG fieldis the same as an SIG field in the preamble in the 802.11a. The HTPreamble part includes an HT-SIG field, an HT-STF, and an HT-LTF. TheHT-SIG field includes two OFDM symbols: HT-SIG1 and HT-SIG2, includesnew signaling information in the 802.11n standard, and is further usedfor auto-detection between an 802.11n data packet and a legacy 802.11adata packet. The HT-STF is used to reset an automatic gain. The HT-LTFincludes one or more OFDM symbols, and is used for multiple-inputmultiple-output (MIMO for short) channel estimation. An HT data field islocated after the HT-LTF.

Schematic structural diagrams of the two symbols HT-SIG1 and HT-SIG2 areshown in FIG. 4. Quantities of subcarriers and modulation and codingmodes of the HT-SIG1 and the HT-SIG2 are the same as those of SIG in the802.11a; therefore, each symbol includes 24 information bits, and 6 bitsof a tail are set to 0, to empty an encoder and a decoder. In theHT-SIG1, the first 7 bits represent an MCS indication, and one MCS isselected from 0-76 to send a subsequent data part. Bit 7 is used toindicate whether data is sent on a bandwidth of 20 MHz or a bandwidth of40 MHz. This information can enable a receiver on a bandwidth of 20 MHzto not receive a signal sent on a bandwidth of 40 MHz, thereby reducingpower consumption. Bits 8 to 23 are used to indicate a length of data,which ranges from 0 to 65535 bytes. In the HT-SIG2, a smooth field atbit 0, a non-detection field at bit 1, and an extended spatial streamsfield at bits 8 to 9 are used to indicate information about sending in abeam forming manner, because the 802.11n supports sending in a beamforming manner. Bit 2 is a reservation bit. Bit 3 is an aggregation bitand is used to indicate whether a data part is a single MAC protocoldata unit (MPDU) or aggregation of MPDUs (A-MPDU for short). Bits 4 to 5represent space time block coding (STBC for short), where 0 representsthat STBC coding is not performed, 3 is a reserved value, and 1 and 2are used to indicate differences between different numbers of space timestreams and different numbers of spatial streams that are obtained whendifferent MCSs are used. A forward error correction (FEC for short)encoding bit is used to indicate whether an encoding mode of data isbinary convolutional coding (BCC for short) or low-density parity-check(LDPC for short) coding. Bit 7 is used to indicate whether a CP in adata transmission part is a short CP (0.4 μs) or a long CP (0.8 μs).Bits 10 to 17 are CRC guard bits and are used to guard bits 0 to 23 ofthe HT-SIG1 and bits 0 to 9 of the HT-SIG2.

FIG. 5 is a schematic structural diagram of a physical layer framestipulated in the 802.11ac standard. A preamble (or a PLCP header) inthe 802.11ac includes two parts: a legacy preamble and a VHT preamble.The L herein mainly refers to a PLCP header part in the 802.11a. Thevery high throughput (VHT for short) herein refers to a PLCP header partin the 802.11ac. To ensure backward compatibility, the L-Preamble partin the preamble in the 802.11ac is the same as an L-Preamble part in apreamble in the 802.11n. The VHT Preamble part includes a VHT-SIGAfield, a VHT-STF, a VHT-LTF, and a VHT-SIGB field. The VHT-SIGA fieldincludes two OFDM symbols: VHT-SIGA1 and VHT-SIGA2, includes newsignaling information in the 802.11ac standard, and is further used forauto-detection between an 802.11ac data packet and legacy 802.11a and802.11n data packets. Structures and functions of the VHT-STF and theVHT-LTF are similar to those of an HT-STF and an HT-LTF. The VHT-SIGBfield is a new field in the preamble in the 802.11ac and is used tosupport a multi-user (MU for short) MIMO function.

Schematic structural diagrams of the two symbols VHT-SIGA1 and VHT-SIGA2are shown in FIG. 6. Quantities of subcarriers and modulation and codingmodes of the HT-SIG-A1 and the VHE-SIG-A2 are the same as those of SIGin the 802.11a; therefore, each symbol includes 24 information bits, and6 bits of a tail are set to 0, to empty an encoder and a decoder. In theVHT-SIG-A1, bits 0 to 1 are used to indicate transmission bandwidth ofdata after the VHT-SIG-A, and 2 bits are used to indicate bandwidths of20 MHz, 40 MHz, 80 MHz, and 160 MHz. Bit 2 is a reservation bit, and bit3 is used to indicate whether STBC is used. Bits 4 to 9 are used toindicate groups during MU-MIMO transmission. During single-user (SU forshort) transmission, a group identifier (ID for short) in a data packetsent to an access point (AP for short) is 0, and a group ID in a datapacket sent by the AP is 1. The rest of bits 4 to 9 indicate groups ofMU. For bits 10 to 21, during SU transmission, bits 10 to 12 are used toindicate a number of space time streams (NSTS for short), and bits 13 to21 are used to indicate some association identifiers (AID for short) ofa station (STA for short) and are used by a receive end to determinewhether to receive information sent by the STA. During MU transmission,bits 10 to 12, bits 13 to 15, bits 16 to 18, and bits 19 to 21 areseparately used to indicate an NSTS carried by data of each user in thegroup. Bit 22 is used to indicate whether a non-AP STA is allowed toenter a sleep state in a transmission opportunity (TXOP for short). Bit23 is a reservation bit. In the VHT-SIG-A2, bit 0 is used to indicatewhether a CP in a data transmission part after the VHT-SIG-A is a shortCP (0.4 μs) or a long CP (0.8 μs). Bit 1 is used to indicate whether asymbol length exceeds a specific value during short CP transmission. Bit2 is used to indicate an encoding mode. During SU transmission, 0represents BCC coding, and 1 represents LDPC coding. During MUtransmission, when MU[0] NSTS indicated by bits 10 to 12 in theVHT-SIG-A1 is a non-zero value, bit 2 being 0 represents BCC coding, andbit 2 being 1 represents LDPC coding; or when MU[0] NSTS is 0, the bitis a reservation bit. Bit 3 is used to indicate whether an extra OFDMsymbol needs to be added when the LDPC coding is used. For bits 4 to 7,during SU transmission, bits 4 to 7 indicate an MCS of datatransmission; during MU transmission, multi-user scenarios of bits 4, 5,and 6 are similar to that of bit 2. Bit 8 is used to indicate whetherbeam forming is used during SU transmission. Bit 9 is a reservation bit.Bits 10 to 17 are consistent with bits 10 to 17 in the HT-SIG2 in the802.11n, and are used to guard bits 0 to 23 of the VHT-SIG-A1 and bits 0to 9 of the VHT-SIG-A2.

The following clearly describes the technical solutions in theembodiments of the present invention with reference to the accompanyingdrawings in the embodiments of the present invention. Apparently, thedescribed embodiments are some but not all of the embodiments of thepresent invention. All other embodiments obtained by persons of ordinaryskill in the art based on the embodiments of the present inventionwithout creative efforts shall fall within the protection scope of thepresent invention.

To facilitate clear description of the technical solutions in theembodiments of the present invention, words such as “first” and “second”are used in the embodiments of the present invention to distinguishbetween the same items or similar items that provide basically the samefunctions or purposes. Persons skilled in the art may understand thatthe words such as “first” and “second” do not restrict the number andthe implementation order.

Embodiment 1

FIG. 7 is a schematic diagram of a network architecture of a WLANapplied in this embodiment of the present invention, and the networkarchitecture of the WLAN 10 includes an AP 20 and multiple STAs 30. TheWLAN 10 supports uplink (UL for short) or downlink (DL) MU MIMOcommunication between the AP 20 and the multiple STAs 30, and the WLAN10 supports UL SU communication or DL SU communication between the AP 20and each STA in the multiple STAs 30.

The AP 20 includes a host processor 21 coupled to a network interface22. The network interface 22 includes a MAC 23 and a PHY 24. The PHY 24includes multiple transceivers (transmit/receive, TX/RX for short) 25,and the transceivers 25 are coupled to multiple antennas 26. In thisembodiment of the present invention, the MAC 23 and the PHY 24 areconfigured to perform operations according to a first communicationsprotocol (for example, the IEEE 802.11ax standard that is in astandardization process at present). Certainly, the MAC 23 and the PHY24 may also be configured to perform operations according to a secondcommunications protocol (for example, the IEEE802.11n standard, theIEEE802.11a standard, and the IEEE802.11ac standard). This is notspecifically limited in this embodiment of the present invention. Thefirst communications protocol herein is referred to as a high efficiencywireless local area network (High Efficiency WLAN, HEW) protocol, andthe second communications protocol herein is referred to as a legacyprotocol.

The STA 30 includes a host processor 31 coupled to a network interface32, and the network interface 32 includes a MAC 33 and a PHY 34. The PHY34 includes multiple transceivers 35, and the transceivers 35 arecoupled to multiple antennas 36. At least one of the multiple STAs 30 isconfigured to perform an operation according to the HEW protocol.

Certainly, the WLAN 10 may further include an L-STA 40, where the L-STA40 is configured to perform an operation according to the legacyprotocol instead of the HEW protocol. This is not specifically limitedin this embodiment of the present invention.

Persons of ordinary skill in the art easily understand that FIG. 7merely exemplarily presents a schematic diagram of a possible networkarchitecture of a WLAN. Certainly, another possible architecture mayfurther exist. This is not specifically limited in this embodiment ofthe present invention.

Persons of ordinary skill in the art easily understand that both astation (STA) side and an AP side may include multiple transceivers andantennas, and FIG. 7 merely exemplarily lists three transceivers andthree antennas on the STA side and the AP side separately, butquantities of the transceivers and the antennas are not limited thereto.This is not specifically limited in this embodiment of the presentinvention.

Persons of ordinary skill in the art easily understand that the WLAN 10may include multiple STAs 30 and multiple L-STAs 40, and FIG. 7 merelyexemplarily lists four STAs 30 and one L-STA 40, but quantities of theSTAs 30 and the L-STAs 40 are not limited thereto. This is notspecifically limited in this embodiment of the present invention.

FIG. 8 is a method for sending signaling in a WLAN according to anembodiment of the present invention, and the method includes:

S801. An AP generates signaling, where the signaling includes an AP IDfield, a bandwidth (BW for short) field, a guard interval (GI for short)field, a CRC field, and a tail field, the AP ID field is used toindicate an ID of the AP, the BW field is used to indicate bandwidthrequired for data transmission subsequent to the signaling, the GI isused to indicate a length of a CP required for data transmissionsubsequent to the signaling, the CRC field is used to guard a fieldbefore the CRC field in the signaling, and the Tail field is used toempty an encoder and a decoder, where the CRC field and the Tail fieldare the last two fields of the signaling.

S802. The AP sends the signaling.

Preferably, in step S801 of this embodiment of the present invention,the AP ID field may be the first field of the signaling. Therefore,after receiving a data packet sent by the AP, a receive end STA side mayfirst parse the AP ID field, to determine whether the received datapacket is a data packet sent by an AP associated with the STA. If thereceived data packet is the data packet sent by the AP associated withthe STA, parsing of the data packet continues. If the received datapacket is not the data packet sent by the AP associated with the STA,parsing of the data packet is stopped, thereby saving system resources.

Exemplarily, an example in which the signaling generated by the AP isreferred to as HEW-SIG1 is used for description. It is assumed that alocation of the HEW-SIG1 in a data frame is shown in FIG. 9, where theHEW-SIG1 is located after an L-Preamble. Therefore, decoding of theHEW-SIG1 is based on channel estimation of the L-Preamble, andtransmission parameters of SIG/SIGA in 802.11a, 802.11n, and 802.11acare still inherited. On a bandwidth of 20 MHz, 52 subcarriers of 64subcarriers are used as useful subcarriers, including four pilotsubcarriers. Those are consistent with transmission parameters of theL-Preamble. The HEW-SIG1 is transmitted by using MCS0, that is,BPSK/quadrature binary phase shift keying (QBPSK for short) modulation,and half-rate BCC coding; therefore, one OFDM symbol carries 24-bitinformation.

As shown in FIG. 10, when the HEW-SIG1 has only one OFDM symbol, exceptthe 8-bit CRC field and the 6-bit Tail field that is used to empty acodec, only 10 bits are available for the AP ID field, the BW field, andthe GI field. The BW field and the GI field each need 2 bits, and the APID field is 6 bits, and may be used to distinguish IDs of 26=64different APs.

Specific content of fields carried on the OFDM symbol of the HEW-SIG1 isshown in Table 1. The 6-bit AP ID field is used to represent IDs of2⁶=64 different APs; the 2-bit BW field is used to represent bandwidthusing scenarios for 20 MHz, 40 MHz, 80 MHz, and 160 MHz; the 2-bit GIfield is used to indicate four CP lengths, where 0.8 and 1.6 aremandatory, and the rest two may be 0.4, 2.4, 3.2, and the like; and theCRC field and the Tail field are consistent with that of SIG/SIGA in the802.11n and the 802.11c.

TABLE 1 Quantity Bit Field of bits Meaning B0-B5 AP ID 6 Used torepresent an ID of an AP. B6-B7 BW 2 0 represents 20 MHz, 1 represents40 MHz, 2 represents 80 MHz, and 3 represents 160 MHz. B8-B9 GI 2 0represents 0.8^(μs), 1 represents 1.6^(μs), and 2 represents 3.2^(μs).B10-B17 CRC 8 Used to guard bits 0 to 9. B18-B23 Tail 6 Used to empty anencoder and a decoder, and all bits are 0.

Persons of ordinary skill in the art easily understand that FIG. 10merely exemplarily presents a possible schematic structural diagram ofHEW-SIG1. Certainly, fields in the HEW-SIG1 may be further arranged inanother manner. This is not specifically limited in this embodiment ofthe present invention.

Further, because to-be-transmitted information bits are limited, bits ofCRC may be compressed, for example, 6 bits are used to perform CRCcheck, and in this case, 12 bits may be used to carry usefulinformation. The 2-bit BW, the 2-bit GI, and the 7-bit AP ID may becarried, and another possible field of the signaling may be furthercarried, or the remaining 1 bit is reserved, as shown in FIG. 11.Certainly, if 4 bits are used to perform check, 14 bits may be used tocarry useful information. Except the carried 2-bit BW, 2-bit GI, and7-bit AP ID, 3 bits may be further used to carry extra information ormay be used as a reservation field. This is not specifically limited inthis embodiment of the present invention.

Further, in the method for sending signaling in a WLAN according to thisembodiment of the present invention, the signaling generated in stepS801 further includes at least one of the following fields: anext-signaling MCS field, a next-signaling length field, a framestructure indication field, an SU/MU field, a transition time field, aduration field, a forward error correction FEC encoding field, a STAquantity field, or a station identifier (STAID for short) length field,where the next-signaling MCS field is used to indicate a transmissionMCS of next signaling, the next-signaling length field is used toindicate a length of the next signaling, the frame structure indicationfield is used to indicate a frame structure of this schedulingtransmission, the SU/MU field is used to indicate whether thisscheduling transmission is SU transmission or MU transmission, thetransition time field is used to indicate a downlink-uplink transitiontime point, the duration field is used to indicate a remaining durationof occupying a channel by this scheduling transmission, the FEC encodingfield is used to indicate a data encoding mode in this schedulingtransmission, the STA quantity field is used to indicate a quantity ofSTAs in this scheduling transmission, and the STAID length field is usedto indicate a length of a STAID of a STA in this schedulingtransmission.

Specifically, in addition to the AP ID field, the BW field, the GIfield, the CRC field, and the Tail field, there may be multiple otherfields in the HEW-SIG1.

Exemplarily, an example in which the next signaling of the HEW-SIG1 ishigh efficiency Wi-Fi Signaling Field 2 (HEW-SIG2) is used fordescription. Similarly, it is assumed that a location of the HEW-SIG1 ina data frame is shown in FIG. 9, one OFDM symbol carries 24-bitinformation, and the HEW-SIG1 includes two 4/s OFDM symbols. As shown inFIG. 12, the HEW-SIG1 may include an AP ID field, a BW field, a GIfield, an HEW-SIG2 MCS field, an HEW-SIG2 length field, a framestructure indication field, a transition time field, an SU/MU field, aCRC field, and a Tail field. An order of the fields and a quantity ofbits of each field are shown in FIG. 12.

Specific content of fields carried on a first OFDM symbol and a secondOFDM symbol in the HEW-SIG1 are respectively shown in Table 2 and Table3. The 7-bit AP ID field is used to represent IDs of 2=128 differentAPs; the 2-bit BW field is used to represent bandwidth using scenariosfor 20 MHz, 40 MHz, 80 MHz, and 160 MHz; the 2-bit GI field is used torepresent four CP lengths, where 0.8 and 1.6 are mandatory, and the resttwo may be 0.4, 2.4, 3.2, and the like; the HEW-SIG2 MCS field and theHEW-SIG2 length field respectively indicate a transmission MCS and alength of the HEW-SIG2; the frame structure indication field is used toindicate an uplink/downlink transmission manner of a frame in thisscheduling transmission; the transition time field is used to indicate adownlink-uplink transition time point; the SU/MU field is used toindicate whether this scheduling transmission is SU transmission or MUtransmission; and the CRC field and the Tail field are consistent withthat of SIG/SIGA in the 802.11n and the 802.11ac.

TABLE 2 Quantity Name Bit Field of bits Meaning HEW- B0-B6 AP ID 7 Usedto represent an SIG1-1 ID of an AP. B7-B8 BW 2 0 represents 20 MHz, 1represents 40 MHz, 2 represents 80 MHz, and 3 represents 160 MHz. B9-B10GI 2 0 represents 0.8^(μs), 1 represents 1.6^(μs), and 2 represents3.2^(μs). B11-B12 HEW-SIG2 2 Indicating that a MCS transmission MCS ofHEW-SIG2 is MCS0-3. B13-B17 HEW-SIG2 5 Indicating a length length ofHEW-SIG2. B18-B19 Frame 2 0 represents DL, structure 1 represents UL,identifier 2 represents DL + UL, and 3 represents reservation. B20-B23Reservation 4

TABLE 3 Quantity Name Bit Field of bits Meaning HEW- B0-B5 Transition 6Indicating a SIG1-1 time downlink-uplink transition time point. B6 SU/MU1 0 represents SU transmission, and 1 represents MU transmission. B7-B9Reservation 3 B10-B17 CRC 8 Used to guard bits 0 to 33 of the HEW-SIG1.B18-B23 Tail 6 Used to empty an encoder and a decoder, and all bits are0.

Persons of ordinary skill in the art easily understand that FIG. 12merely exemplarily presents a possible schematic structural diagram ofHEW-SIG1. Certainly, the HEW-SIG1 may further include another field, andfields in the HEW-SIG1 may be further arranged in another manner. Thisis not specifically limited in this embodiment of the present invention.

Exemplarily, a schematic structural diagram of HEW-SIG1 may be shown inFIG. 13. Compared with the HEW-SIG1 provided in FIG. 12, a durationfield and an FEC encoding field are added to the HEW-SIG1 provided inFIG. 13, and a frame structure indication field and a transition timefield are removed.

Alternatively, exemplarily, a schematic structural diagram of HEW-SIG1may be shown in FIG. 14, where the HEW-SIG1 includes three 4 μs OFDMsymbols. This is not specifically limited in this embodiment of thepresent invention.

It should be noted that a reservation field of the HEW-SIG1 in schematicstructural diagrams of the HEW-SIG1 provided above may be used toindicate another signaling. This is not specifically limited in thisembodiment of the present invention.

It should be noted that, in this embodiment of the present invention,some fields of the HEW-SIG1 may be reused. Exemplarily, in the schematicstructural diagram of the HEW-SIG1 shown in FIG. 12, when the framestructure indication field indicates that a frame structure of thisscheduling transmission is an uplink structure or a downlink structure,the transition time field is not needed, and in this case, 6 bits of thetransition time field may be reused for another signaling bit, forexample, information such as an MCS for transmitting an acknowledgmentcharacter (ACK for short). This is not specifically limited in thisembodiment of the present invention.

It should be noted that, a STA field may also be used to indicatewhether this scheduling transmission is SU transmission or MUtransmission. For example, if a value of the STA field is 1, it mayindicate that this scheduling transmission is the SU transmission; or ifa value of the STA field is not 1, it may indicate that this schedulingtransmission is the MU transmission.

Further, in the method for sending signaling in a WLAN according to thisembodiment of the present invention, if the frame structure indicationfield indicates that the frame structure of this scheduling transmissionis the uplink structure, after the AP sends the signaling (step S802),the method may further include: receiving, by the AP, an uplink datapacket sent by the STA; and sending, by the AP, an acknowledgmentmessage to the STA, where the acknowledgment message is used to indicatethat the AP receives the uplink data packet.

Specifically, in this embodiment of the present invention, when only theuplink data packet exists, a frame structure format may be shown in FIG.15. First, the AP sends a channel reserved packet (CRP for short), toenter a scheduling transmission stage. Then the AP sends an L-Preambleand an HEW Preamble, where the HEW Preamble includes HEW-SIG1, anHEW-STF, an HEW-LTF, and HEW-SIG2. The HEW-SIG2 includes a resourceallocation indication in an uplink transmission stage. The STA performsuplink transmission on an indicated resource in a following uplinktransmission timeslot according to the resource allocation indication inthe HEW-SIG2. If still only uplink data exists in the following, afterthe first uplink transmission timeslot ends, the AP sends an ACK of justreceived uplink data and indicates a resource allocation status of anext uplink timeslot. If uplink data transmission ends, the AP sendsonly an ACK of just received uplink data.

A media access protocol (MAP for short) in FIG. 15 is the resourceallocation indication.

Optionally, in the method for sending signaling in a WLAN according tothis embodiment of the present invention, if the frame structureindication field indicates that the frame structure of this schedulingtransmission is the downlink structure, after the AP sends the signaling(step S802), the method may further include: sending, by the AP, adownlink data packet to the STA; and receiving, by the AP, anacknowledgment message sent by the STA, where the acknowledgment messageis used to indicate that the STA receives the downlink data packet.

Specifically, in this embodiment of the present invention, when only thedownlink data packet exists, a frame structure format may be shown inFIG. 16. First, the AP sends a CRP, to enter a scheduling transmissionstage. Then the AP sends downlink data, where an initial part of thedownlink data includes an L-Preamble and an HEW Preamble. The HEWPreamble includes HEW-SIG1, an HEW-STF, an HEW-LTF, and HEW-SIG2. Thedownlink data is sent immediately after the HEW Preamble. The HEW-SIG2includes a resource allocation indication in a downlink transmissionstage and/or a resource indication of replying an ACK in the uplink. TheSTA receives the downlink data on a corresponding resource according tothe resource allocation indication in the HEW-SIG2. After downlink datatransmission ends, the STA sends the ACK of the just received downlinkdata.

Optionally, in the method for sending signaling in a WLAN according tothis embodiment of the present invention, if the frame structureindication field indicates that the frame structure of this schedulingtransmission is a structure cascading downlink and uplink, after the APsends the signaling (step S802), the method may further include:sending, by the AP, a downlink data packet to the STA; receiving, by theAP, an uplink data packet and a first acknowledgment message that aresent by the STA, where the first acknowledgment message is used toindicate that the STA receives the downlink data packet; and sending, bythe AP, a second acknowledgment message to the STA, where the secondacknowledgment message is used to indicate that the AP receives theuplink data packet.

Specifically, in this embodiment of the present invention, when both thedownlink data packet and the uplink data packet exist, a frame structureformat may be shown in FIG. 17. First, the AP sends a CRP, to enter ascheduling transmission stage. Then the AP sends an L-Preamble and anHEW Preamble. The HEW Preamble includes HEW-SIG1, an HEW-STF, anHEW-LTF, and HEW-SIG2. The HEW-SIG2 includes resource locations ofreceiving, on the STA side, data in a downlink transmission timeslot andsending, on the STA side, data in an uplink transmission timeslot. Ifdownlink data and uplink data still exist after one downlinktransmission and uplink transmission end, after the uplink data ends,downlink transmission and uplink transmission continue, starting fromthe downlink data. In an uplink transmission time period, transmissionof an ACK reply for the downlink data is included; and in a downlinktransmission time period, transmission of an ACK of the uplink data isincluded. If transmission finally ends with an uplink timeslot,transmission of an ACK reply of the AP for uplink transmission needs tobe followed, as shown in the last part of FIG. 17.

Certainly, if the frame structure indication field indicates that theframe structure of this scheduling transmission is a structure cascadingdownlink and uplink, after the AP sends the signaling (step S802), themethod may further include: receiving, by the AP, an uplink data packetsent by the STA; sending, by the AP, a downlink data packet and a secondacknowledgment message to the STA, where the second acknowledgmentmessage is used to indicate that the AP receives the uplink data packet;and receiving, by the AP, a first acknowledgment message sent by theSTA, where the first acknowledgment message is used to indicate that theSTA receives the downlink data packet.

This embodiment of the present invention imposes no specific limitationon this.

Further, if the downlink-uplink transition time point is T, a value M ofthe transition time field is:M=(T−End time of the next signaling)/Time domain length of each resourceunit during this scheduling  Formula (1)

Specifically, in a case of 20 MHz data transmission and 256-point FastFourier Transform (FFT for short), a symbol length is 12.8 μs, and a CPlength of 0.8 μs is added; it may be obtained that the shortest OFDMsymbol length is 13.6 μs in the case of 20 MHz data transmission and256-point FFT. The longest length that can be indicated in the SIG inthe L-Preamble is 5484 μs, and an L-Preamble length of 20 μs issubtracted; the remaining 5464 μs is used to transmit a Preamble anddata in an HEW part. Assuming that a time domain of a resource unit in ascheduling stage includes n OFDM symbols, a maximum quantity of possibledownlink-uplink switch points is M=5464/13.6/n. Assuming that n=8, themaximum quantity of downlink-uplink switch points is M=5464/13.6/8≈50.If the transition time field occupies 6 bits, 2⁶=64 switch points can beindicated, and all the downlink-uplink switch points that exist when n=8can be indicated. Certainly, if time domains of resource units includedifferent quantities of OFDM symbols, quantities of bits required by thetransition time field are different. This is not specifically limited inthis embodiment of the present invention.

The method for sending signaling in a WLAN according to this embodimentof the present invention includes: generating, by an AP, signaling,where the signaling includes an AP ID field, a BW field, a GI field, aCRC field, and a Tail field, the AP ID field is used to indicate an IDof the AP, the BW field is used to indicate bandwidth required for datatransmission subsequent to the signaling, the GI is used to indicate alength of a CP required for data transmission subsequent to thesignaling, the CRC field is used to guard a field before the CRC fieldin the signaling, and the Tail field is used to empty an encoder and adecoder, where the CRC field and the Tail field are the last two fieldsof the signaling; and sending, by the AP, the signaling. The foregoingsolution provides an OFDMA-based design solution for common signaling ina WLAN system, thereby resolving a prior-art problem that there is noOFDMA-based design solution for common signaling in the WLAN system.

FIG. 18 is a method for receiving signaling in a WLAN according to anembodiment of the present invention, and the method includes:

S1801. A STA receives signaling sent by an access point (AP), where thesignaling includes an AP ID field, a BW field, a GI field, a CRC field,and a Tail field, the AP ID field is used to indicate an ID of the AP,the BW field is used to indicate bandwidth required for datatransmission subsequent to the signaling, the GI is used to indicate alength of a CP required for data transmission subsequent to thesignaling, the CRC field is used to guard a field before the CRC fieldin the signaling, and the Tail field is used to empty an encoder and adecoder, where the CRC field and the Tail field are the last two fieldsof the signaling.

S1802. The STA parses the AP ID field, the BW field, and the GI field torespectively obtain the ID of the AP, and the bandwidth and the lengthof the CP that are required for data transmission subsequent to thesignaling.

If the ID of the AP does not match an AP ID associated with the STA,parsing of a field after the AP ID field is stopped.

Specifically, in step S1801 of this embodiment of the present invention,for a schematic structural diagram of the signaling received by the STA,reference may be made to FIG. 10, and details are not repeatedlydescribed in this embodiment of the present invention.

Preferably, in step S1801 of this embodiment of the present invention,the AP ID field may be the first field of the signaling. Therefore,after receiving a data packet sent by the AP, the STA may first parsethe AP ID field, to determine whether the received data packet is a datapacket sent by an AP associated with the STA. If the received datapacket is the data packet sent by the AP associated with the STA,parsing of the data packet continues. If the received data packet is notthe data packet sent by the AP associated with the STA, parsing of thedata packet is stopped, thereby saving system resources.

Further, in the method for receiving signaling in a WLAN according tothis embodiment of the present invention, the signaling may furtherinclude at least one of the following fields: a field of a transmissionMCS of next signaling of the signaling, a next-signaling length field, aframe structure indication field, an SU/MU field, a transition timefield, a duration field, an FEC encoding field, a STA quantity field, ora STAID length field, where the next-signaling MCS field is used toindicate the transmission MCS of the next signaling, the next-signalinglength field is used to indicate a length of the next signaling, theframe structure indication field is used to indicate a frame structureof this scheduling transmission, the SU/MU field is used to indicatewhether this scheduling transmission is SU transmission or MUtransmission, the transition time field is used to indicate adownlink-uplink transition time point, the duration field is used toindicate a remaining duration of occupying a channel by this schedulingtransmission, the FEC encoding field is used to indicate a data encodingmode in this scheduling transmission, the STA quantity field is used toindicate a quantity of STAs in this scheduling transmission, and theSTAID length field is used to indicate a length of a STAID of a STA inthis scheduling transmission, where the frame structure of thisscheduling transmission includes an uplink structure, a downlinkstructure, or a structure cascading downlink and uplink.

The method for receiving signaling in a WLAN according to thisembodiment of the present invention may further include: parsing, by theSTA, the at least one of the following fields to obtain at least onepiece of the following information: the MCS of the next signaling, thelength of the next signaling, the frame structure of this schedulingtransmission, whether this scheduling transmission is the SUtransmission or the MU transmission, the downlink-uplink transition timepoint, the remaining duration of occupying the channel by thisscheduling transmission, the data encoding mode in this schedulingtransmission, the quantity of stations STAs in this schedulingtransmission, or the length of the STAID of the STA in this schedulingtransmission.

Specifically, in this embodiment of the present invention, for aschematic structural diagram of the signaling received by the STA,reference may be made to FIG. 12 to FIG. 14, and details are notrepeatedly described in this embodiment of the present invention.

Further, the method for receiving signaling in a WLAN according to thisembodiment of the present invention may further include: reading, by theSTA, resource indication information in the next signaling; determining,by the STA, a resource location of the STA according to the resourceindication information; and transmitting, by the STA, an uplink datapacket and/or a downlink data packet at the resource location.

Exemplarily, if the AP ID field is the first field of the signaling, andthe schematic structural diagram of the signaling received by the STA isspecifically shown in FIG. 12, a schematic flowchart of parsingsignaling HEW-SIG1 by the STA after receiving a data packet is providedherein. As shown in FIG. 19A and FIG. 19B, a procedure includes thefollowing steps:

S1901. The STA parses an AP ID field to obtain an ID of an AP.

S1902. The STA determines, according to the ID of the AP, whether thereceived data packet is a data packet sent by an AP associated with theSTA.

If the received data packet is the data packet sent by the AP associatedwith the STA, step S1903 is performed; or if the received data packet isnot the data packet sent by the AP associated with the STA, theprocedure ends.

S1903. The STA parses a BW field, a GI field, an HEW-SIG2 transmissionMCS field, and an HEW-SIG2 length field, to respectively obtainbandwidth and a length of a CP that are required for subsequent datatransmission of the HEW-SIG1, a transmission MCS of the HEW-SIG2, and alength of the HEW-SIG2.

S1904. The STA parses a frame structure indication field to obtain aframe structure of this scheduling transmission.

S1905. The STA determines whether the frame structure of this schedulingtransmission is a structure cascading downlink and uplink.

If the frame structure of this scheduling transmission is the structurecascading downlink and uplink, step S1906 is performed; or if the framestructure of this scheduling transmission is not the structure cascadingdownlink and uplink, step S1907 is performed.

S1906. The STA parses a transition time field to obtain adownlink-uplink transition time point.

S1907. The STA parses an SU/MU field to learn whether this schedulingtransmission is SU transmission or MU transmission.

If this scheduling transmission is the SU transmission, step S1908 isperformed; or if this scheduling transmission is the MU transmission,step S1909 is performed.

S1908. If this scheduling transmission is the SU transmission, receiveor send data according to a carrier allocation format in the SUtransmission.

S1909. If this scheduling transmission is the MU transmission, the STAreads resource indication information in the HEW-SIG2.

S1910. The STA determines, according to the resource indicationinformation in the HEW-SIG2, a resource location of receiving or sendingdata by the STA, and receives or sends data at the correspondingresource location.

At this point, the procedure of parsing the signaling HEW-SIG1 ends.

It should be noted that, when SU transmission is performed, becausesubsequent transmission resources are only used by one user, theresource indication information in the HEW-SIG2 is not needed. However,when MU transmission is performed, locations in which a STA receives(downlink) and sends (uplink) data need to be indicated in the HEW-SIG2;and when the MU transmission is performed, to ensure receiving andsending quality, it is ensured as much as possible that pilots exist inboth a receiving part and a sending part of each STA. Therefore,allocation structures of subcarriers are different during the SUtransmission and the MU transmission, and more pilot design is requiredfor the MU transmission compared with the SU transmission. Inconclusion, the SU/MU field may be added to indicate whether thisscheduling transmission is the SU transmission or the MU transmission.

Further, if the signaling includes the transition time field, that theSTA parses the transition time field to obtain the downlink-uplinktransition time point specifically includes: determining, by the STA,the downlink-uplink transition time point according to a value of thetransition time field, a time domain length of a resource unit, and anend time of the signaling with reference to a preset formula, where thepreset formula includes:Transition time point=Value of transition time field×Time domain lengthof the resource unit+End time of the next signaling  Formula (2)

Exemplarily, if the value of the transition time field is 010100, wherethe value is 20 after being converted to a decimal number, and a timedomain of each resource unit during this scheduling includes eight OFDMsymbols, a time domain length of each resource unit during thisscheduling is 13.6×8=108.8 μs, and it can be obtained, according toformula (2), that the downlink-uplink transition time point during thisscheduling=an end time of HEW-SIG2+20×108.8 μs=the end time of theHEW-SIG2+2176 μs. A location of the transition time point is shown inFIG. 20.

Further, if the signaling further includes the frame structureindication field, and the frame structure indication field indicatesthat the frame structure of this scheduling transmission is thestructure cascading downlink and uplink, a time domain location of anuplink transmission resource is:Sending time of the uplink transmission resource=Transition timepoint+Receiving-to-sending switch time+Uplink time indicated in the nextsignaling  Formula (3)

Exemplarily, the foregoing example continues to be used, and it isassumed that the downlink-uplink transition time point during thisscheduling=the end time of the HEW-SIG2+20×108.8 μs=the end time of theHEW-SIG2+2176 μs, the receiving-to-sending transition time is 16 μs, anda transmission time of the STA indicated in the HEW-SIG2 is 25 μs afteruplink transmission starts; it can be obtained, according to formula(3), that the sending time of an uplink transmission resource=the endtime of the HEW-SIG2+2176 μs+16 μs+25 μs=the end time of theHEW-SIG2+2217 μs. The time domain location of the uplink transmissionresource is shown in FIG. 21, where a receive/transmit transition gap(RTG for short) is the receiving-to-sending switch time in formula (3),and an uplink time indicated in the HEW-SIG2 is the uplink timeindicated in the next signaling in formula (3). The STA may obtain thetime domain location of the uplink transmission resource by means ofcalculation according to formula (3).

The method for receiving signaling in a WLAN according to thisembodiment of the present invention includes: receiving, by a STA,signaling sent by an AP, where the signaling includes an AP ID field, aBW field, a GI field, a CRC field, and a Tail field, the AP ID field isused to indicate an ID of the AP, the BW field is used to indicatebandwidth required for data transmission subsequent to the signaling,the GI is used to indicate a length of a CP required for datatransmission subsequent to the signaling, the CRC field is used to guarda field before the CRC field in the signaling, and the Tail field isused to empty an encoder and a decoder, where the CRC field and the Tailfield are the last two fields of the signaling; and parsing, by the STA,the AP ID field, the BW field, and the GI field to respectively obtainthe ID of the AP, and the bandwidth and the length of the CP that arerequired for data transmission subsequent to the signaling, where if theID of the AP does not match an AP ID associated with the STA, parsing ofa field after the AP ID field is stopped. The foregoing solutionprovides an OFDMA-based design solution for common signaling in a WLANsystem, thereby resolving a prior-art problem that there is noOFDMA-based design solution for common signaling in the WLAN system.

Embodiment 2

This embodiment of the present invention provides an AP 2200.Specifically, as shown in FIG. 22, the AP 2200 includes a generationunit 2202 and a sending unit 2203.

The generation unit 2202 is configured to generate signaling, where thesignaling includes an AP ID field, a bandwidth BW field, a guardinterval GI field, a cyclic redundancy check CRC field, and a tailfield, the AP ID field is used to indicate an ID of the AP 2200, the BWfield is used to indicate bandwidth required for data transmissionsubsequent to the signaling, the GI is used to indicate a length of a CPrequired for data transmission subsequent to the signaling, the CRCfield is used to guard a field before the CRC field in the signaling,and the Tail field is used to empty an encoder and a decoder, where theCRC field and the Tail field are the last two fields of the signaling.

The sending unit 2203 is configured to send the signaling.

Preferably, the AP ID field is the first field of the signaling.

Further, the signaling further includes at least one of the followingfields: a next-signaling MCS field, a next-signaling length field, aframe structure indication field, an SU/MU field, a transition timefield, a duration field, a forward error correction FEC encoding field,a STA quantity field, or a STAID length field, where the next-signalingMCS field is used to indicate a transmission MCS of the next signaling,the next-signaling length field is used to indicate a length of the nextsignaling, the frame structure indication field is used to indicate aframe structure of this scheduling transmission, the SU/MU field is usedto indicate whether this scheduling transmission is SU transmission orMU transmission, the transition time field is used to indicate adownlink-uplink transition time point, the duration field is used toindicate a remaining duration of occupying a channel by this schedulingtransmission, the FEC encoding field is used to indicate a data encodingmode in this scheduling transmission, the STA quantity field is used toindicate a quantity of STAs in this scheduling transmission, and theSTAID length field is used to indicate a length of a STAID of a STA inthis scheduling transmission, where the frame structure of thisscheduling transmission includes an uplink structure, a downlinkstructure, or a structure cascading downlink and uplink.

Further, as shown in FIG. 23, the AP 2200 further includes a receivingunit 2204.

The receiving unit 2204 is configured to: if the frame structureindication field indicates that the frame structure of this schedulingtransmission is the uplink structure, after the sending unit 2203 sendsthe signaling, receive an uplink data packet sent by the STA; and thesending unit 2203 is further configured to send an acknowledgmentmessage to the STA, where the acknowledgment message is used to indicatethat the AP 2200 receives the uplink data packet.

Optionally, as shown in FIG. 23, the AP 2200 further includes areceiving unit 2204.

The sending unit 2203 is further configured to: if the frame structureindication field indicates that the frame structure of this schedulingtransmission is the downlink structure, send a downlink data packet tothe STA after sending the signaling; and the receiving unit 2204 isconfigured to receive an acknowledgment message sent by the STA, wherethe acknowledgment message is used to indicate that the STA receives thedownlink data packet.

Optionally, as shown in FIG. 23, the AP 2200 further includes areceiving unit 2204.

The sending unit 2203 is further configured to: if the frame structureindication field indicates that the frame structure of this schedulingtransmission is the structure cascading downlink and uplink, send adownlink data packet to the STA after sending the signaling; thereceiving unit 2204 is configured to receive an uplink data packet and afirst acknowledgment message that are sent by the STA, where the firstacknowledgment message is used to indicate that the STA receives thedownlink data packet; and the sending unit 2203 is further configured tosend a second acknowledgment message to the STA, where the secondacknowledgment message is used to indicate that the AP 2200 receives theuplink data packet; or the receiving unit 2204 is further configured to:if the frame structure indication field indicates that the framestructure of this scheduling transmission is the structure cascadingdownlink and uplink, after the sending unit 2203 sends the signaling,receive an uplink data packet sent by the STA; the sending unit 2203 isfurther configured to send a downlink data packet and a secondacknowledgment message to the STA, where the second acknowledgmentmessage is used to indicate that the AP 2200 receives the uplink datapacket; and the receiving unit 2204 is further configured to receive afirst acknowledgment message sent by the STA, where the firstacknowledgment message is used to indicate that the STA receives thedownlink data packet.

Further, if the downlink-uplink transition time point is T, a value M ofthe transition time field is:M=(T−End time of the next signaling)/Time domain length of each resourceunit during this scheduling

Specifically, for a method for sending signaling in a WLAN by using anAP, reference may be made to the description in Embodiment 1, anddetails are not repeatedly described in this embodiment of the presentinvention.

Because the AP in this embodiment can be configured to execute themethod in the foregoing Embodiment 1, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

Embodiment 3

This embodiment of the present invention provides a STA 2400.Specifically, as shown in FIG. 24, the STA 2400 includes a receivingunit 2401 and a parsing unit 2402.

The receiving unit 2401 is configured to receive signaling sent by anAP, where the signaling includes an AP identifier ID field, a bandwidthBW field, a guard interval GI field, a cyclic redundancy check CRCfield, and a tail field, the AP ID field is used to indicate an ID ofthe AP, the BW field is used to indicate bandwidth required for datatransmission subsequent to the signaling, the GI is used to indicate alength of a cyclic prefix CP required for data transmission subsequentto the signaling, the CRC field is used to guard a field before the CRCfield in the signaling, and the Tail field is used to empty an encoderand a decoder, where the CRC field and the Tail field are the last twofields of the signaling.

The parsing unit 2402 is configured to parse the AP ID field, the BWfield, and the GI field to respectively obtain the ID of the AP, and thebandwidth and the length of the CP that are required for datatransmission subsequent to the signaling.

If the ID of the AP does not match an AP ID associated with the STA2400, parsing of a field after the AP ID field is stopped.

Preferably, the AP ID field is the first field of the signaling.

Further, the signaling further includes at least one of the followingfields: a field of a transmission modulation and coding scheme (MCS) ofnext signaling of the signaling, a next-signaling length field, a framestructure indication field, a single-user (SU)/multi-user (MU) field, atransition time field, a duration field, a forward error correction FECencoding field, a STAs 2400 quantity field, or a STA2400ID length field,where the next-signaling MCS field is used to indicate the transmissionMCS of the next signaling, the next-signaling length field is used toindicate a length of the next signaling, the frame structure indicationfield is used to indicate a frame structure of this schedulingtransmission, the SU/MU field is used to indicate whether thisscheduling transmission is SU transmission or MU transmission, thetransition time field is used to indicate a downlink-uplink transitiontime point, the duration field is used to indicate a remaining durationof occupying a channel by this scheduling transmission, the FEC encodingfield is used to indicate a data encoding mode in this schedulingtransmission, the STAs 2400 quantity field is used to indicate aquantity of STAs in this scheduling transmission, and the STAID lengthfield is used to indicate a length of a STAID of a STA in thisscheduling transmission, where the frame structure of this schedulingtransmission includes an uplink structure, a downlink structure, or astructure cascading downlink and uplink.

The parsing unit 2402 is further configured to parse the at least one ofthe following fields to obtain at least one piece of the followinginformation: the transmission MCS of the next signaling, the length ofthe next signaling, the frame structure of this scheduling transmission,whether this scheduling transmission is the SU transmission or the MUtransmission, the downlink-uplink transition time point, the remainingduration of occupying the channel by this scheduling transmission, thedata encoding mode in this scheduling transmission, the quantity ofstations STAs in this scheduling transmission, or the length of theSTAID of the STA in this scheduling transmission.

Further, as shown in FIG. 25, the STA 2400 further includes a readingunit 2403, a determining unit 2404, and a sending unit 2405.

The reading unit 2403 is configured to read resource indicationinformation in the next signaling; the determining unit 2404 isconfigured to determine a resource location of the STA 2400 according tothe resource indication information; and the receiving unit 2401 isconfigured to receive a downlink data packet at the resource location;or the sending unit 2405 is configured to send an uplink data packet atthe resource location.

Further, if the signaling further includes the transition time field,the parsing unit 2402 is specifically configured to: determine thedownlink-uplink transition time point according to a value of thetransition time field, a time domain length of a resource unit, and anend time of the signaling with reference to a preset formula, where thepreset formula includes: Transition time point=Value of transition timefield×Time domain length of the resource unit+End time of the nextsignaling.

Further, if the signaling further includes the frame structureindication field, and the frame structure indication field indicatesthat the frame structure of this scheduling transmission is thestructure cascading downlink and uplink, a time domain location of anuplink transmission resource is: Sending time of the uplink transmissionresource=Transition time point+Receiving-to-sending switch time+Uplinktime indicated in the next signaling.

Specifically, for a method for receiving signaling in a WLAN by using aSTA, reference may be made to the description in Embodiment 1, anddetails are not repeatedly described in this embodiment of the presentinvention.

Because the STA in this embodiment can be configured to execute themethod in the foregoing Embodiment 1, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

Embodiment 4

This embodiment of the present invention provides an AP 2600.Specifically, as shown in FIG. 26, the AP 2600 includes a processor 2601and a transmitter 2602.

The processor 2601 is configured to generate signaling, where thesignaling includes an AP ID field, a bandwidth BW field, a guardinterval GI field, a cyclic redundancy check CRC field, and a tailfield, the AP ID field is used to indicate an ID of the AP 2600, the BWfield is used to indicate bandwidth required for data transmissionsubsequent to the signaling, the GI is used to indicate a length of a CPrequired for data transmission subsequent to the signaling, the CRCfield is used to guard a field before the CRC field in the signaling,and the Tail field is used to empty an encoder and a decoder, where theCRC field and the Tail field are the last two fields of the signaling.

The transmitter 2602 is configured to send the signaling.

Preferably, the AP ID field is the first field of the signaling.

Further, the signaling further includes at least one of the followingfields: a next-signaling MCS field, a next-signaling length field, aframe structure indication field, an SU/MU field, a transition timefield, a duration field, a forward error correction FEC encoding field,a STA quantity field, or a STAID length field, where the next-signalingMCS field is used to indicate a transmission MCS of the next signaling,the next-signaling length field is used to indicate a length of the nextsignaling, the frame structure indication field is used to indicate aframe structure of this scheduling transmission, the SU/MU field is usedto indicate whether this scheduling transmission is SU transmission orMU transmission, the transition time field is used to indicate adownlink-uplink transition time point, the duration field is used toindicate a remaining duration of occupying a channel by this schedulingtransmission, the FEC encoding field is used to indicate a data encodingmode in this scheduling transmission, the STA quantity field is used toindicate a quantity of STAs in this scheduling transmission, and theSTAID length field is used to indicate a length of a STAID of a STA inthis scheduling transmission, where the frame structure of thisscheduling transmission includes an uplink structure, a downlinkstructure, or a structure cascading downlink and uplink.

Further, as shown in FIG. 27, the AP 2600 further includes a receiver2603.

The receiver 2603 is configured to: if the frame structure indicationfield indicates that the frame structure of this scheduling transmissionis the uplink structure, after the transmitter 2602 sends the signaling,receive an uplink data packet sent by the STA; and the transmitter 2602is further configured to send an acknowledgment message to the STA,where the acknowledgment message is used to indicate that the AP 2600receives the uplink data packet.

Optionally, as shown in FIG. 27, the AP 2600 further includes a receiver2603, where the transmitter 2602 is further configured to: if the framestructure indication field indicates that the frame structure of thisscheduling transmission is the downlink structure, send a downlink datapacket to the STA after sending the signaling; and the receiver 2603 isconfigured to receive an acknowledgment message sent by the STA, wherethe acknowledgment message is used to indicate that the STA receives thedownlink data packet.

Optionally, as shown in FIG. 27, the AP 2600 further includes a receiver2603, where the transmitter 2602 is further configured to: if the framestructure indication field indicates that the frame structure of thisscheduling transmission is the structure cascading downlink and uplink,send a downlink data packet to the STA after sending the signaling; thereceiver 2603 is configured to receive an uplink data packet and a firstacknowledgment message that are sent by the STA, where the firstacknowledgment message is used to indicate that the STA receives thedownlink data packet; and the transmitter 2602 is further configured tosend a second acknowledgment message to the STA, where the secondacknowledgment message is used to indicate that the AP 2600 receives theuplink data packet; or the receiver 2603 is further configured to: ifthe frame structure indication field indicates that the frame structureof this scheduling transmission is the structure cascading downlink anduplink, after the transmitter 2602 sends the signaling, receive anuplink data packet sent by the STA; the transmitter 2602 is furtherconfigured to send a downlink data packet and a second acknowledgmentmessage to the STA, where the second acknowledgment message is used toindicate that the AP 2600 receives the uplink data packet; and thereceiver 2603 is further configured to receive a first acknowledgmentmessage sent by the STA, where the first acknowledgment message is usedto indicate that the STA receives the downlink data packet.

Further, if the downlink-uplink transition time point is T, a value M ofthe transition time field is:M=(T−End time of the next signaling)/Time domain length of each resourceunit during this scheduling

Specifically, for a method for sending signaling in a WLAN by using anAP, reference may be made to the description in Embodiment 1, anddetails are not repeatedly described in this embodiment of the presentinvention.

Because the AP in this embodiment can be configured to execute themethod in the foregoing Embodiment 1, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

Embodiment 5

This embodiment of the present invention provides a STA 2800.Specifically, as shown in FIG. 28, the STA 2800 includes a receiver 2801and a processor 2802.

The receiver 2801 is configured to receive signaling sent by an accesspoint AP, where the signaling includes an AP identifier ID field, abandwidth BW field, a guard interval GI field, a cyclic redundancy checkCRC field, and a tail field, the AP ID field is used to indicate an IDof the AP, the BW field is used to indicate bandwidth required for datatransmission subsequent to the signaling, the GI is used to indicate alength of a cyclic prefix CP required for data transmission subsequentto the signaling, the CRC field is used to guard a field before the CRCfield in the signaling, and the Tail field is used to empty an encoderand a decoder, where the CRC field and the Tail field are the last twofields of the signaling.

The processor 2802 is configured to parse the AP ID field, the BW field,and the GI field to respectively obtain the ID of the AP, and thebandwidth and the length of the CP that are required for datatransmission subsequent to the signaling, where if the ID of the AP doesnot match an AP ID associated with the STA 2800, parsing of a fieldafter the AP ID field is stopped.

Preferably, the AP ID field is the first field of the signaling.

Further, the signaling further includes at least one of the followingfields: a field of a transmission modulation and coding scheme MCS ofnext signaling of the signaling, a next-signaling length field, a framestructure indication field, a SU/MU field, a transition time field, aduration field, a forward error correction FEC encoding field, a STAquantity field, or a STAID length field, where the next-signaling MCSfield is used to indicate the transmission MCS of the next signaling,the next-signaling length field is used to indicate a length of the nextsignaling, the frame structure indication field is used to indicate aframe structure of this scheduling transmission, the SU/MU field is usedto indicate whether this scheduling transmission is SU transmission orMU transmission, the transition time field is used to indicate adownlink-uplink transition time point, the duration field is used toindicate a remaining duration of occupying a channel by this schedulingtransmission, the FEC encoding field is used to indicate a data encodingmode in this scheduling transmission, the STA quantity field is used toindicate a quantity of STAs in this scheduling transmission, and theSTAID length field is used to indicate a length of a STAID of a STA inthis scheduling transmission, where the frame structure of thisscheduling transmission includes an uplink structure, a downlinkstructure, or a structure cascading downlink and uplink.

The processor 2802 is further configured to parse the at least one ofthe following fields to obtain at least one piece of the followinginformation: the transmission MCS of the next signaling, the length ofthe next signaling, the frame structure of this scheduling transmission,whether this scheduling transmission is the SU transmission or the MUtransmission, the downlink-uplink transition time point, the remainingduration of occupying the channel by this scheduling transmission, thedata encoding mode in this scheduling transmission, the quantity ofstations STAs in this scheduling transmission, or the length of theSTAID of the STA in this scheduling transmission.

Further, the STA 2800 further includes a transmitter 2803.

The processor 2802 is further configured to read resource indicationinformation in the next signaling, and determine a resource location ofthe STA 2800 according to the resource indication information; and thereceiver 2801 is further configured to receive a downlink data packet atthe resource location; or the transmitter 2803 is configured to send anuplink data packet at the resource location.

Further, if the signaling includes the transition time field, theprocessor 2802 is specifically configured to: determine thedownlink-uplink transition time point according to a value of thetransition time field, a time domain length of a resource unit, and anend time of the signaling with reference to a preset formula, where thepreset formula includes: Transition time point=Value of transition timefield×Time domain length of the resource unit+End time of the nextsignaling.

Further, if the signaling further includes the frame structureindication field, and the frame structure indication field indicatesthat the frame structure of this scheduling transmission is thestructure cascading downlink and uplink, a time domain location of anuplink transmission resource is: Sending time of the uplink transmissionresource=Transition time point+Receiving-to-sending switch time+Uplinktime indicated in the next signaling.

Specifically, for a method for receiving signaling in a WLAN by using aSTA, reference may be made to the description in Embodiment 1, anddetails are not repeatedly described in this embodiment of the presentinvention.

Because the STA in this embodiment can be configured to execute themethod in the foregoing Embodiment 1, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

Embodiment 6

This embodiment of the present invention provides a method for sendingsignaling in a WLAN, and the method is specifically applied to ascenario in which only SU transmission exists. As shown in FIG. 30, themethod includes.

S3001. An AP generates signaling, where the signaling includes an AP IDfield, a BW field, an SU/MU field, a GI field, a STAID field, a field ofan MCS of data in a non-preamble part, an FEC encoding field, an STBCfield, a field of a number of spatial streams (NSS for short), anaggregation field, a smooth field, a CRC field, and a Tail field.

The AP ID field is used to indicate an ID of the AP, the BW field isused to indicate bandwidth required for data transmission subsequent tothe signaling, the SU/MU field is used to indicate that thistransmission is the SU transmission, the GI field is used to indicate alength of a CP required for data transmission subsequent to thesignaling, the STAID field is used to indicate an identifier of a STA inthis transmission, the field of the transmission MCS of the data in thenon-preamble part is used to indicate the transmission MCS of the datain the non-preamble part, the FEC encoding field is used to indicate adata encoding mode of the data in the non-preamble part, the STBC fieldis used to indicate whether data transmission subsequent to thesignaling in the SU transmission is performed in an STBC manner, the NSSfield is used to indicate a quantity of streams used in the SUtransmission, the aggregation field is used to indicate whether the datain the non-preamble part is a single MPDU or aggregation of MPDUs, thesmooth field is used to indicate information about sending in a beamforming manner, the CRC field is used to guard a field before the CRCfield in the signaling, and the Tail field is used to empty an encoderand a decoder, where the CRC field and the Tail field are the last twofields of the signaling.

S3002. The AP sends the signaling.

Specifically, an example in which the signaling generated by the AP isreferred to as HEW-SIG1 is used for description. It is assumed that alocation of the HEW-SIG1 in a data frame is shown in FIG. 9, one OFDMsymbol carries 24-bit information, and the HEW-SIG1 includes two 4 μsOFDM symbols; in the scenario in which only SU transmission exists, asshown in FIG. 31, the HEW-SIG1 includes an AP ID field, a BW field, anSU/MU field, a GI field, a STAID field, a field of an MCS of data in anon-preamble part, an FEC encoding field, an STBC field, an NSS field,an aggregation field, a smooth field, a CRC field, and a tail field. Anorder of the fields and a quantity of bits of each field are shown inFIG. 31.

It should be noted that, in this example, the NSS field is indicated byusing 3 bits. That 000 represents one spatial stream, 001 represents twospatial streams, 010 represents three spatial streams, 011 representsfour spatial streams, 100 represents five spatial streams, 101represents six spatial streams, 110 represents seven spatial streams,and 111 represents eight spatial streams may be designed.

It should be noted that, in this example, the smooth field is used toindicate information about sending in a beam forming manner, andspecifically, may instruct a receive end to determine, according towhether beam forming is performed, whether channel smoothing can beperformed.

It should be noted that, in this embodiment of the present invention, anindication manner of the field of the transmission MCS of the data inthe non-preamble part is the same as an indication manner of an MCSfield in a current standard (such as 802.11a, 802.11n, or 802.11ac), anindication manner of the STBC field is the same as an indication mannerof an STBC field in a current standard (such as 802.11n or 802.11ac),and indication manners of the aggregation field and the smooth field arethe same as indication manners of an aggregation field and a smoothfield in a current standard (such as 802.11n). This is not specificallylimited in this embodiment of the present invention.

It should be noted that a structure shown in FIG. 31 is applicable toboth uplink transmission and downlink transmission. Specifically,whether uplink transmission or downlink transmission is performed may bedetermined according to an AP ID, a STAID, and a received/sent signal.For example, if a STA is a receive end, and an AP is a transmit end,after receiving and parsing signaling sent by the AP, the STA learnsthat an AP ID included in the signaling matches an ID of an APassociated with the STA, and then the downlink transmission may bedetermined. Optionally, a UL/DL indication field may be further added toFIG. 31. This is not specifically limited in this embodiment of thepresent invention.

It should be noted that FIG. 31 exemplarily presents a structural designsolution of HEW-SIG1. Certainly, a location of a specific field, asymbol in which a specific field is located, and a quantity of bits usedby each field in FIG. 31 all may be adjusted, for example, the STAIDfield may be indicated by using 5-10 bits, and the NSS field may beindicated by using 2 bits or 4 bits. This is not specifically limited inthis embodiment of the present invention.

An embodiment of the present invention further provides a method forsending signaling in a WLAN, and the method is specifically applied to ascenario in which only SU transmission exists. As shown in FIG. 32, themethod includes:

S3201. A STA receives signaling sent by an AP, where the signalingincludes an AP ID field, a BW field, an SU/MU field, a GI field, a STAIDfield, a field of an MCS of data in a non-preamble part, an FEC encodingfield, an STBC field, an NSS field, an aggregation field, a smoothfield, a CRC field, and a Tail field.

The AP ID field is used to indicate an ID of the AP, the BW field isused to indicate bandwidth required for data transmission subsequent tothe signaling, the SU/MU field is used to indicate that thistransmission is the SU transmission, the GI field is used to indicate alength of a CP required for data transmission subsequent to thesignaling, the STAID field is used to indicate an identifier of a STA inthis transmission, the field of the transmission MCS of the data in thenon-preamble part is used to indicate the transmission MCS of the datain the non-preamble part, the FEC encoding field is used to indicate adata encoding mode of the data in the non-preamble part, the STBC fieldis used to indicate whether data transmission subsequent to thesignaling in the SU transmission is performed in an STBC manner, the NSSfield is used to indicate a quantity of streams used in the SUtransmission, the aggregation field is used to indicate whether the datain the non-preamble part is a single MPDU or aggregation of MPDUs, thesmooth field is used to indicate information about sending in a beamforming manner, the CRC field is used to guard a field before the CRCfield in the signaling, and the Tail field is used to empty an encoderand a decoder, where the CRC field and the Tail field are the last twofields of the signaling.

S3202. The STA parses the AP ID field, the BW field, the SU/MU field,the GI field, the STAID field, the field of the transmission MCS of thedata in the non-preamble part, the FEC encoding field, the STBC field,the NSS field, the aggregation field, and the smooth field torespectively obtain the following information: an ID of the AP,bandwidth and a length of a CP that are required for data transmissionsubsequent to the signaling, that this transmission is the SUtransmission, an identifier of a STA in this transmission, thetransmission MCS of the data in the non-preamble part, a data encodingmode of the data in the non-preamble part, whether data transmissionsubsequent to the signaling in the SU transmission is performed in anSTBC manner, a quantity of streams used in the SU transmission, whetherthe data in the non-preamble part is a single MPDU or aggregation ofMPDUs, and information about beam forming, where if the ID of the APdoes not match an AP ID associated with the STA, parsing of a fieldafter the AP ID field is stopped.

Specifically, in this embodiment of the present invention, for aschematic structural diagram of the signaling received by the STA,reference may be made to FIG. 31, and details are not repeatedlydescribed in this embodiment of the present invention.

It is assumed that the schematic structural diagram of the signalingreceived by the STA is shown in FIG. 31. A schematic flowchart ofparsing signaling HEW-SIG1 by the STA after receiving a data packet isprovided herein. As shown in FIG. 33A and FIG. 33B, a procedure includesthe following steps.

S3301. Parse an AP ID field to obtain an ID of an AP with which the STAperforms current transmission.

S3302. Determine, according to the ID of the AP, whether the receiveddata packet is a data packet sent by an AP associated with the STA.

If the received data packet is the data packet sent by the AP associatedwith the STA, step S3303 is performed; or if the received data packet isnot the data packet sent by the AP associated with the STA, theprocedure ends.

S3303. Parse a BW field to obtain bandwidth required for subsequent datatransmission of the HEW-SIG1.

S3304. Parse an SU/MU field to learn that this transmission is SUtransmission.

S3305. Read a STAID field to obtain information about an identifier of aSTA in this transmission.

S3306. Parse a field of a transmission MCS of data in a non-preamblepart and an FEC encoding field, to determine information about atransmission MCS and a data encoding mode that are of the data in thenon-preamble part in this transmission.

S3307. Parse an STBC field and an NSS field, to determine whethersubsequent data transmission of the HEW-SIG1 in this transmission isperformed in an STBC manner and information about a quantity of streamsused in the SU transmission.

S3308. Parse an aggregation field and a smooth field, to determinewhether the data in the non-preamble part is a single MPDU oraggregation of MPDUs and information about beam forming.

S3309. Receive subsequent data of the HEW-SIG1 in this transmissionaccording to the parsed information about the transmission MCS and thedata encoding mode that are of the data in the non-preamble part in thistransmission, information about whether the subsequent data transmissionof the HEW-SIG1 in this transmission is performed in the STBC manner,information about the quantity of streams used in the SU transmission,information about whether the data in the non-preamble part in thistransmission is a single MPDU or aggregation of MPDUs, and informationabout beam forming.

It should be noted that, if this transmission is MU transmission, theSTA may receive data according to a carrier allocation format of MU.This is not specifically limited in this embodiment of the presentinvention.

Optionally, in the method for sending signaling in a WLAN according tothis embodiment of the present invention, in a scenario of SUtransmission, signaling may also be generated by the STA, and the APreceives the signaling sent by the STA, where a structure of thesignaling is the same as that in FIG. 31, and a schematic flowchart ofparsing signaling HEW-SIG1 by the AP after receiving the signaling issimilar to FIG. 33A and FIG. 33B. A difference lies only in that, if theAP parses the signaling HEW-SIG1, the “determine, according to the ID ofthe AP, whether the received data packet is a data packet sent by an APassociated with the STA” in step S3302 needs to be replaced with“determine, according to the ID of the AP, whether the data packet issent to the AP”. This case is not described in detail in this embodimentof the present invention, and for details, reference may be made to thedescription in the foregoing embodiment.

The foregoing solution provides an OFDMA-based design solution forcommon signaling in a WLAN system, thereby resolving a prior-art problemthat there is no OFDMA-based design solution for common signaling in theWLAN system.

Embodiment 7

This embodiment of the present invention provides a method for sendingsignaling in a WLAN. As shown in FIG. 34, the method includes.

S3401. An AP generates signaling, where the signaling includes an AP IDfield, a BW field, a GI field, a frame structure indication field, adownlink/uplink STA quantity field, a CRC field, and a Tail field.

The AP ID field is used to indicate an ID of the AP, the BW field isused to indicate bandwidth required for data transmission subsequent tothe signaling, the GI is used to indicate a length of a CP required fordata transmission subsequent to the signaling, the frame structureindication field is used to indicate that a frame structure of thisscheduling transmission is a structure cascading downlink and uplink,the downlink/uplink STA quantity field is used to indicate a quantity ofdownlink/uplink users in this scheduling transmission, the CRC field isused to guard a field before the CRC field in the signaling, and theTail field is used to empty an encoder and a decoder, where the CRCfield and the Tail field are the last two fields of the signaling.

S3402. The AP sends the signaling.

Specifically, the downlink/uplink STA quantity field is introduced inthis embodiment of the present invention. If the frame structureindication field indicates that the frame structure of this schedulingtransmission is the structure cascading downlink and uplink, thedownlink/uplink STA quantity field in this transmission is read, todetermine whether the signaling in resource indication informationindicates a downlink transmission resource or an uplink transmissionresource.

It should be noted that, the signaling in this embodiment of the presentinvention may further include another field in addition to the AP IDfield, the BW field, the GI field, the frame structure indication field,the downlink/uplink STA quantity field, the CRC field, and the Tailfield. This is not specifically limited in this embodiment of thepresent invention.

An example in which the signaling generated by the AP is referred to asHEW-SIG1 is used for description. It is assumed that a location of theHEW-SIG1 in a data frame is shown in FIG. 9, one OFDM symbol carries24-bit information, and the HEW-SIG1 includes two 4 μs OFDM symbols.Exemplarily, as shown in FIG. 35, the HEW-SIG1 includes an AP ID field,a BW field, an SU/MU field, a GI field, a frame structure indicationfield, a downlink STA quantity field, a transition time field, anHEW-SIG2 MCS field, an HEW-SIG2 length field, a CRC field, and a tailfield. An order of the fields and a quantity of bits of each field areshown in FIG. 31.

Exemplarily, assuming that the HEW-SIG1 includes three 4 μs OFDMsymbols, as shown in FIG. 36, the HEW-SIG1 includes an AP ID field, aduration field, a BW field, an SU/MU field, a GI field, an HEW-SIG2 MCSfield, an HEW-SIG2 MCS field, a frame structure indication field, a STAquantity field, a downlink STA quantity field, a STAID length field, atransition time field, a CRC field, and a tail field. An order of thefields and a quantity of bits of each field are shown in FIG. 36.

It should be noted that FIG. 35 and FIG. 36 exemplarily presentstructural design solutions of HEW-SIG1. Certainly, a location of aspecific field, a symbol in which a specific field is located, and aquantity of bits used by each field in FIG. 35 and FIG. 36 may beadjusted. This is not specifically limited in this embodiment of thepresent invention.

An embodiment of the present invention provides a method for sendingsignaling in a WLAN. As shown in FIG. 37, the method includes.

S3701. A STA receives signaling sent by an AP, where the signalingincludes an AP ID field, a BW field, a GI field, a frame structureindication field, a downlink/uplink STA quantity field, a CRC field, anda Tail field.

The AP ID field is used to indicate an ID of the AP, the BW field isused to indicate bandwidth required for data transmission subsequent tothe signaling, the GI is used to indicate a length of a CP required fordata transmission subsequent to the signaling, the frame structureindication field is used to indicate that a frame structure of thisscheduling transmission is a structure cascading downlink and uplink,the downlink/uplink STA quantity field is used to indicate a quantity ofdownlink/uplink users in this scheduling transmission, the CRC field isused to guard a field before the CRC field in the signaling, and theTail field is used to empty an encoder and a decoder, where the CRCfield and the Tail field are the last two fields of the signaling.

S3702. The STA parses the AP ID field, the BW field, the GI field, theframe structure indication field, and the downlink/uplink STA quantityfield to respectively obtain the following information: an ID of the AP,bandwidth and a length of a CP that are required for data transmissionsubsequent to the signaling, that a frame structure of this schedulingtransmission is a structure cascading downlink and uplink, and aquantity of downlink/uplink users in this scheduling transmission, whereif the ID of the AP does not match an AP ID associated with the STA,parsing of a field after the AP ID field is stopped.

Specifically, in this embodiment of the present invention, for aschematic structural diagram of the signaling received by the STA,reference may be made to FIG. 35 and FIG. 36, and details are notrepeatedly described in this embodiment of the present invention.

Specifically, assuming that the schematic structural diagram of thesignaling received by the STA is specifically shown in FIG. 35, afterreading the frame structure indication field of the HEW-SIG1 to learnthat the frame structure of this scheduling transmission is thestructure cascading downlink and uplink, the STA further reads adownlink STA quantity field, to determine a quantity of users scheduledin the downlink. For example, if k users are scheduled in the downlink,when reading resource allocation information and reading the first kpieces of resource allocation information of the STAs, the STA learnsthat information that has been allocated at this time is downlinkinformation, and information allocated after the k pieces of resourceallocation information is uplink information. Therefore, there is noneed to indicate, in each piece of resource allocation information of aSTA, that the allocation information is downlink allocation informationor uplink allocation information.

Certainly, in a signaling structure shown in FIG. 35, the downlink STAquantity field may be replaced with an uplink STA quantity field. Theuplink STA quantity field is used to indicate a quantity of uplink usersin this scheduling transmission, that is, a quantity of users scheduledin the uplink. After reading the frame structure indication field of theHEW-SIG1 to learn that the frame structure of this schedulingtransmission is the structure cascading downlink and uplink, the STAfurther reads the uplink STA quantity field, to determine the quantityof users scheduled in the uplink. It is assumed that k users arescheduled in the uplink, when reading resource allocation informationand reading the first k pieces of resource allocation information of theSTAs, the STA learns that information that has been allocated at thistime is uplink information, and information allocated after the k piecesof resource allocation information is downlink information. Similarly,there is no need to indicate, in each piece of resource allocationinformation of a STA, that the allocation information is uplinkallocation information or downlink allocation information.

Specifically, assuming that the schematic structural diagram of thesignaling received by the STA is specifically shown in FIG. 36, the STAmay determine, according to a STA quantity field and the downlink STAquantity field, whether resource allocation indication information is adownlink indication or an uplink indication; therefore, there is no needto add an indication indicating whether allocation information isdownlink allocation information or uplink allocation information to theresource allocation indication information for each piece of allocationinformation. For example, if a quantity of scheduled STAs is 16, and aquantity of downlink STAs is 8, the first eight pieces of resourceallocation information are downlink allocation information indications,and the remaining eight pieces of resource allocation information areuplink allocation information indications.

Similarly, the downlink STA quantity field in FIG. 36 may also bereplaced with an uplink STA quantity field. The uplink STA quantityfield is used to indicate a quantity of uplink users in this schedulingtransmission, that is, a quantity of users scheduled in the uplink. Ausing principle is the same as that in the foregoing method. Forexample, if a quantity of scheduled STAs is 16, and a quantity of uplinkSTAs is 8, the first eight pieces of resource allocation information areuplink allocation information indications, and the remaining eightpieces of resource allocation information are downlink allocationinformation indications. In this way, it may be implemented that thereis no need to add an indication indicating whether allocationinformation is downlink allocation information or uplink allocationinformation to the resource allocation indication information for eachpiece of allocation information.

The foregoing solution provides an OFDMA-based design solution forcommon signaling in a WLAN system, thereby resolving a prior-art problemthat there is no OFDMA-based design solution for common signaling in theWLAN system.

Embodiment 8

This embodiment of the present invention provides a STA 3800. As shownin FIG. 38, the STA 3800 includes a generation unit 3801 and a sendingunit 3802.

The generation unit 3801 is configured to generate signaling if thistransmission is SU transmission, where the signaling includes an accesspoint identifier AP ID field, a bandwidth BW field, an SU/multi-user MUfield, a guard interval GI field, a station identifier STAID field, afield of a transmission modulation and coding scheme MCS of data in anon-preamble part, a forward error correction FEC encoding field, aspace time block coding STBC field, a number of spatial streams NSSfield, an aggregation field, a smooth field, a cyclic redundancy checkCRC field, and a tail field, the AP ID field is used to indicate an IDof the AP, the BW field is used to indicate bandwidth required for datatransmission subsequent to the signaling, the SU/MU field is used toindicate that this transmission is the SU transmission, the GI field isused to indicate a length of a cyclic prefix CP required for datatransmission subsequent to the signaling, the STAID field is used toindicate an identifier of a STA in this transmission, the field of thetransmission MCS of the data in the non-preamble part is used toindicate the transmission MCS of the data in the non-preamble part, theFEC encoding field is used to indicate a data encoding mode of the datain the non-preamble part, the STBC field is used to indicate whetherdata transmission subsequent to the signaling in the SU transmission isperformed in an STBC manner, the NSS field is used to indicate aquantity of streams used in the SU transmission, the aggregation fieldis used to indicate whether the data in the non-preamble part is asingle media access control protocol data unit MPDU or aggregation ofMPDUs, the smooth field is used to indicate information about sending ina beam forming manner, the CRC field is used to guard a field before theCRC field in the signaling, and the Tail field is used to empty anencoder and a decoder, where the CRC field and the Tail field are thelast two fields of the signaling.

The sending unit 3802 is configured to send the signaling.

Because the STA 3800 in this embodiment can be configured to execute themethod in the foregoing Embodiment 6, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

Embodiment 9

This embodiment of the present invention provides an AP 3900. As shownin FIG. 39, the AP 3900 includes a receiving unit 3901 and a parsingunit 3902.

The receiving unit 3901 is configured to: if this transmission is SUtransmission, receive signaling sent by a station STA, where thesignaling includes an AP identifier ID field, a bandwidth BW field, anSU/MU field, a guard interval GI field, a station identifier STAIDfield, a field of a transmission modulation and coding scheme MCS ofdata in a non-preamble part, a forward error correction FEC encodingfield, a space time block coding STBC field, a number of spatial streamsNSS field, an aggregation field, a smooth field, a cyclic redundancycheck CRC field, and a tail field, the AP ID field is used to indicatean ID of the AP 3900, the BW field is used to indicate bandwidthrequired for data transmission subsequent to the signaling, the SU/MUfield is used to indicate that this transmission is the SU transmission,the GI field is used to indicate a length of a cyclic prefix CP requiredfor data transmission subsequent to the signaling, the STAID field isused to indicate an identifier of a STA in this transmission, the fieldof the transmission MCS of the data in the non-preamble part is used toindicate the transmission MCS of the data in the non-preamble part, theFEC encoding field is used to indicate a data encoding mode of the datain the non-preamble part, the STBC field is used to indicate whetherdata transmission subsequent to the signaling in the SU transmission isperformed in an STBC manner, the NSS field is used to indicate aquantity of streams used in the SU transmission, the aggregation fieldis used to indicate whether the data in the non-preamble part is asingle MPDU or aggregation of MPDUs, the smooth field is used toindicate information about sending in a beam forming manner, the CRCfield is used to guard a field before the CRC field in the signaling,and the Tail field is used to empty an encoder and a decoder, where theCRC field and the Tail field are the last two fields of the signaling.

The parsing unit 3902 is configured to parse the AP ID field, the BWfield, the GI field, the SU/MU field, the STAID field, the field of thetransmission MCS of the data in the non-preamble part, the FEC encodingfield, the STBC field, the NSS field, the aggregation field, and thesmooth field to respectively obtain the following information: the ID ofthe AP 3900, the bandwidth and the length of the CP that are requiredfor data transmission subsequent to the signaling, that thistransmission is the SU transmission, the identifier of the STA in thistransmission, the transmission MCS of the data in the non-preamble part,the data encoding mode of the data in the non-preamble part, whether thedata transmission subsequent to the signaling in the SU transmission isperformed in the STBC manner, the quantity of streams used in the SUtransmission, whether the data in the non-preamble part is a single MPDUor aggregation of MPDUs, and the information about beam forming, whereif the ID of the AP does not match an AP ID of the AP, parsing of afield after the AP ID field is stopped.

Because the AP 3900 in this embodiment can be configured to execute themethod in the foregoing Embodiment 6, for a technical effect that can beachieved in this embodiment, reference may be made to the description inthe foregoing embodiment, and details are not repeatedly describedherein.

The foregoing descriptions are merely specific implementation manners ofthe present embodiments, but are not intended to limit the protectionscope of the present embodiments. Any variation or replacement readilyfigured out by persons skilled in the art within the technical scopedisclosed in the present embodiments shall fall within the protectionscope of the present embodiments. Therefore, the protection scope of thepresent embodiments shall be subject to the protection scope of theclaims.

Persons skilled in the art may understand that, in addition to FIG. 9, aframe structure involved in the present embodiments may be further shownin FIG. 9a , where in an uplink frame or a downlink frame, signalingHEW-SIG1 is located after a legacy preamble, or signaling HEW-SIG2 isfurther included, and the signaling HEW-SIG1 may include HE-SIG-A orfurther include HE-SIG-B. Specifically, the uplink frame may alsoinclude a legacy preamble (L-preamble) and signaling HEW SIG1. HEW-SIG2in the downlink frame, and the L-preamble, the HEW-SIG1, or HEW-SIG2 inthe uplink frame are optional. HE-SIG-A or HE-SIG-B in the HEW-SIG1 isalso optional.

In the downlink frame, the HEW SIG1 may be divided into two parts. Afirst part (which may be referred to as HE-SIG-A) is transmitted byusing a fixed MCS, that is, a symbol length and a quantity of symbolsare fixed, to transmit basic signaling and determine that the radioframe is in a lax frame format. For a second part (which may be referredto as HE-SIG-B), a variable length and different quantities of symbolsmay be used, where the variable length herein means that a CP length isselected according to a channel environment. The CP length and thequantity of symbols of the HE-SIG-B may be indicated in the HE-SIG-A. Inan SU scenario, for the HE-SIG-B, the length and the quantity of symbolsmay be variable, or the CP length may be fixed, or the quantity ofsymbols is fixed, or both the CP length and the quantity of symbols arefixed. Signaling for a specific STA may also be placed at a start partof a resource allocated by the STA, for example, the HEW-SIG2 in thedownlink frame in FIG. 9 a.

In an MU scenario, when the first signaling HE-SIG-A is repeatedlytransmitted, in a subcarrier allocation manner in the 802.11a, on eachbandwidth of 20 MHz of a channel in a BSS established by an AP, fieldsof a first signaling HE-SIG-A may be further in formats shown in FIG.40a , FIG. 40b , and FIG. 40c . A schematic flowchart of parsing thesignaling HEW-SIG-A by a receive end after receiving a data packet isexemplarily provided herein, as shown in FIG. 41. In the MU scenario,for indication manners of the HE-SIG-A shown in FIG. 40a , FIG. 40b ,and FIG. 40c , resource indication information and a configurationparameter of a specific data part such as a transmission MCS, aSTAID/GID, a number of transmitted space time streams, an indication ofa specific resource location, an indication that is for each STA andindicates whether LDPC is used, or an indication indicating whether STBCis used are placed in the HE-SIG-B for indicating.

As shown in FIG. 41, FIG. 41 is a schematic flowchart of parsingsignaling HEW-SIG-A by a STA. In general, the STA sequentially parsescontent in the HEW-SIG-A and performs a corresponding operationaccording to content obtained by parsing, and details are not repeatedlydescribed herein.

Certainly, an implementation manner of the present embodiments furtherincludes another specific frame structure. For example, when an SU/MUfield indicates SU transmission, that is, in an SU scenario, when thefirst signaling HE-SIG-A is repeatedly transmitted, in the subcarrierallocation manner in the 802.11a, on each bandwidth of 20 MHz of thechannel in the BSS established by the AP, the first signaling HE-SIG-Amay include two OFDM symbols, and signaling information carried on eachOFDM symbol is shown in FIG. 40d . Optionally, the HE-SIG-A may includefour OFDM symbols, where the second OFDM symbol has content of the firstOFDM symbol, and the fourth OFDM symbol has content of the third OFDMsymbol, that is, the second OFDM and the fourth OFDM symbols arerespectively repetitions of the first OFDM symbol and the third OFDM ina time domain. In this case, content carried on the first symbol, thesecond symbol, the third symbol, and the fourth symbol are shown in FIG.40e . Optionally, each OFDM symbol may also be repeated in a frequencydomain, and each OFDM symbol carries 12-bit information. Content, of theHE-SIG-A, carried by using four OFDM symbols that are repeated in thefrequency domain may be represented by using FIG. 40 e.

Optionally, during SU transmission, to ensure transmission reliabilityof the HE-SIG-A, when symbols of the HE-SIG-A are repeated in a timedomain, only two repeated symbols may be used to carry information ofthe HE-SIG-A. As shown in FIG. 40f , the second OFDM symbol is arepetition of the first OFDM in the time domain. Optionally, each symbolmay be repeated in a frequency domain of the symbol, and in this case,content, of the HE-SIG-A, carried on the two symbols may also berepresented by using FIG. 40f . When the HE-SIG-A is carried by usingonly two symbols repeated in the time domain or in the frequency domainshown in FIG. 40f , some common signaling needs to be indicated in theHE-SIG-B. The HE-SIG-B may not be transmitted in atime-domain-repetition or frequency-domain-repetition transmissionmanner, but is independently transmitted on each symbol. Optionally, theHE-SIG-B may be transmitted by using a high-order MCS. Optionally, theHE-SIG-B may not be repeatedly transmitted on each bandwidth of 20 MHz,but is transmitted on an entire channel in the BSS established by theAP. Optionally, the HE-SIG-B may be repeatedly transmitted on eachbandwidth of 20 MHz. When the HE-SIG-B is transmitted on a bandwidth of20 MHz by using an MCS0, content carried by the HE-SIG-B may be shown inFIG. 40g and FIG. 40h . FIG. 40g shows the HE-SIG-B carried by usingonly one symbol during SU transmission, and FIG. 40h shows content ofthe HE-SIG-B carried by using two symbols during SU transmission.Optionally, when the HE-SIG-B is transmitted by using a high-order MCShigher than the MCS0 or by using a bandwidth greater than 20 MHz, someor all content carried by the HE-SIG-B may be consistent with FIG. 40gand FIG. 40h , and only combinations of fields on an OFDM symbol may bedifferent.

Optionally, during SU transmission, three OFDM symbols may be used tocarry the content of the HE-SIG-A, where each symbol is repeated in thefrequency domain; therefore, each OFDM symbol can carry 12-bitinformation. The content, of the HE-SIG-A, carried on the three OFDMsymbols may be separately shown in FIG. 40i , FIG. 40j , and FIG. 40l .When the HE-SIG-A shown in FIG. 40i is used, the HE-SIG-B part may notbe needed. When the HE-SIG-A shown in FIG. 40j is used, the HE-SIG-Bpart is needed to supplement a signaling indication during SUtransmission. The HE-SIG-B may not be transmitted in atime-domain-repetition or frequency-domain-repetition transmissionmanner, but is independently transmitted on each symbol. Optionally, theHE-SIG-B may be transmitted by using a high-order MCS. Optionally, theHE-SIG-B may not be repeatedly transmitted on each bandwidth of 20 MHz,but is transmitted on an entire channel in the BSS established by theAP. Optionally, the HE-SIG-B may be repeatedly transmitted on eachbandwidth of 20 MHz. When the HE-SIG-B is transmitted on a bandwidth of20 MHz by using an MCS0, content carried by the HE-SIG-B may be shown inFIG. 40k , where one OFDM symbol is used to carry the content of theHE-SIG-B. Optionally, when the HE-SIG-B is transmitted by using ahigh-order MCS higher than the MCS0 or by using a bandwidth greater than20 MHz, some or all content carried by the HE-SIG-B may be consistentwith FIG. 40k , and only combinations of fields on an OFDM symbol may bedifferent. During SU transmission and when the HE-SIG-A shown in FIG.40l is used, the HE-SIG-B part is needed to supplement a signalingindication during the SU transmission. The HE-SIG-B may not betransmitted in a time-domain-repetition or frequency-domain-repetitiontransmission manner, but is independently transmitted on each symbol.Optionally, the HE-SIG-B may be transmitted by using a high-order MCS.Optionally, the HE-SIG-B may not be repeatedly transmitted on eachbandwidth of 20 MHz, but is transmitted on an entire channel in the BSSestablished by the AP. Optionally, the HE-SIG-B may be repeatedlytransmitted on each bandwidth of 20 MHz. When the HE-SIG-B istransmitted on a bandwidth of 20 MHz by using an MCS0, content carriedby the HE-SIG-B may be shown in FIG. 40m , where two OFDM symbols areused to carry the content of the HE-SIG-B. Optionally, when the HE-SIG-Bis transmitted by using a high-order MCS higher than the MCS0 or byusing a bandwidth greater than 20 MHz, some or all content carried bythe HE-SIG-B may be consistent with FIG. 40m , and only combinations offields on an OFDM symbol may be different.

When a signaling structure of HE-SIG-1 is shown in FIG. 40f to FIG. 40m, FIG. 42 exemplarily shows a schematic flowchart of parsing thesignaling HEW-SIG-1 by a receive end after receiving a data packet, anddetails are not repeatedly described herein.

In another example, in a structure shown in FIG. 9a , and in a case ofSU transmission, a structure, a field, or a sequence of HE-SIG-1 in adownlink frame may be the same as those in an uplink frame. In a case ofMU transmission, content, the structure, and the sequence of theHE-SIG-1 in the downlink frame are described in the foregoingembodiment: and a structure, a field, or a sequence of HE-SIG-1 in theuplink frame, especially a structure, a field, or a sequence of HE-SIG-Amay be consistent with those of HE-SIG-A in the downlink frame, butspecifically carried content may be different.

Specifically, during uplink transmission, the HE-SIG-A is repeatedlytransmitted, in a subcarrier allocation manner in the 802.11a, on eachbandwidth of 20 MHz of a channel in a BSS established by an AP. Duringuplink multi-user transmission, to enable the AP and/or another STA toparse the HE-SIG-A, a STA that performs uplink multi-user transmissionneeds to transmit the same content in the HE-SIG-A, to ensure thatformed air-interface waveforms are consistent. Same waveforms sent bymultiple STAs are superposed in the air, so as to form a samewavelength. In this case, HE-SIG-A of each STA carries the same content.Because the STA or the AP learns whether transmission is downlinktransmission or uplink transmission only after parsing the HE-SIG-A, aquantity of symbols, a field, and a structure of HE-SIG-A transmitted inthe uplink needs to be consistent with those of HE-SIG-A transmitted inthe downlink.

To ensure that waveforms of HE-SIG-As sent in the uplink by all STAs inmulti-user transmission are consistent, content of fields of theHE-SIG-As sent by all the STAs needs to be the same. Because schedulingis performed by an AP in uplink transmission, and a receive end in theuplink transmission is the AP, the AP knows related parameterinformation and resource configuration information of the uplinktransmission. In this way, transmission parameters and resourceconfiguration information of HE-SIG-A in the uplink multi-usertransmission may be configured by default, for example, values of fieldsin HE-SIG-As of all STAs in the uplink multi-user transmission are setto 0, or to a specific default field or sequence.

However, some fields need to indicate corresponding information to areceive end or another STA, and the fields cannot be set to a defaultvalue, but need to indicate corresponding information according to anactual status. These fields include but are not limited to an SU/MUindication field, an AP ID field, a TXOP transmission duration field,and the like. The SU/MU indication field needs to indicate that afollowing radio frame is single-user transmission SU or multi-usertransmission MU; therefore, the indication needs to be performedaccording to an actual status, so that the receive end performsreceiving according to a correct frame format. The AP ID field is usedto indicate information about an AP related to the wireless packet, sothat another AP or STA determines whether the radio frame is related tothe AP or STA. If the radio frame is related to the AP or STA, the AP orSTA continues to receive and parse the wireless packet. If the radioframe is not related to the AP or STA, the AP or STA directly quitsreceiving or stops parsing. Therefore, the AP ID field also needs toperform indication according to an actual status, and cannot be randomlyconfigured by default. The TXOP transmission duration field is used toindicate a remaining duration of a current scheduling period of an AP,so that another AP or STA obtains information about the remainingduration of occupying a channel, and configures NAV information.Therefore, the TXOP transmission duration field also needs to beconfigured according to an actual status, instead of being randomlyconfigured by default.

It should be noted that, even if the SU/MU indication field, the AP IDfield, the TXOP transmission duration field, and the like need toperform indication according to an actual status and cannot be randomlyconfigured, configurations of the fields of STAs in uplink multi-usertransmission need to be the same, that is, content carried by SU/MUindication fields, AP ID fields, and TXOP transmission duration fieldsof the STAs in uplink multi-user transmission need to be identical. TheSU/MU indication field is used to indicate single-user transmission ormulti-user transmission, and therefore, the SU/MU indication fields ofthe STAs in the uplink multi-user transmission are easily consistentwith each other. The AP ID field is used to indicate information aboutan AP related to a following radio frame, and because the STAs in uplinkmulti-user transmission perform uplink transmission to a same AP, the APID fields of the STAs in uplink multi-user transmission are easilyconsistent with each other. The TXOP transmission duration field is usedto indicate a remaining duration of a current scheduling period of anAP, so that another AP or STA obtains information about the remainingduration of occupying a channel, and configures NAV information. For theSTAs in uplink multi-user transmission, the information is consistent;but, the information needs to be calculated according to a TXOPtransmission duration and a duration of a downlink frame that areindicated in an SIG part in the downlink frame. Optionally, aninter-frame duration of transition between a downlink and an uplink, anda duration of a preamble (the preamble may include two parts: a legacypreamble and an HEW-preamble) before a downlink frame and/or an uplinkframe are further needed to perform calculation.

It should be noted that, the SU herein means that only one station(user) performs transmission, and the MU means that multiple stations(users) simultaneously perform transmission, and includes but is notlimited to manners such as MU-MIMO and OFDMA. The foregoing figures anddescriptions thereof are examples of content carried by the HE-SIG-A orthe HE-SIG-B, and a specific order of fields may be adjusted, or onlysome fields or a combination of some fields may be carried.

What is claimed is:
 1. A method, comprising: generating, by an accesspoint (AP), a data frame, wherein the data frame includes a highefficiency Wi-Fi Signaling Field 1 (HEW-SIG1), the HEW-SIGs comprises aframe structure indication field, and the frame structure indicationfield indicates a frame structure of a scheduling transmission, whereinthe frame structure of the scheduling transmission comprises an uplinkstructure or a downlink structure, the scheduling transmission of thedata frame is a multi-user transmission, the data frame furthercomprises a high efficiency Wi-Fi Signaling Field 2 (HEW-SIG2), theHEW-SIG2 is adjacent to the HEW-SIGs in the data frame, the HEW-SIG2comprises resource indication information, and the HEW-SIGs furthercomprises a HEW-SIG2 modulation and coding scheme (HEW-SIG2 MCS) field,and the HEW-SIG2 MCS field indicates a transmission modulation andcoding scheme (MCS) of the HEW-SIG2; and sending, by the AP, the dataframe.
 2. The method according to claim 1, wherein the resourceindication information in the HEW-SIG2 comprises resource locations forcommunicating data by multiple users.
 3. The method according to claim1, wherein the HEW-SIGs further comprises a transition time fieldindicating a downlink-uplink transition time point, and a value M of thetransition time field is:M=(T−End time of the HEW-SIG2)/Time domain length of each resource unitof the scheduling transmission; and wherein T is the downlink-uplinktransition time point.
 4. The method according to claim 1, wherein theHEW-SIGs further comprises a HEW-SIG2 length field and a duration field,wherein the HEW-SIG2 length field indicates a length of HEW-SIG2signaling, and the duration field indicates a remaining duration ofoccupying a channel.
 5. A method, comprising: receiving, by a station, adata frame, wherein the data frame includes a high efficiency Wi-FiSignaling Field 1 (HEW-SIG1), the HEW-SIGs comprises a frame structureindication field, the frame structure indication field indicates a framestructure of a scheduling transmission, wherein the frame structure ofthe scheduling transmission comprises an uplink structure or a downlinkstructure, the scheduling transmission of the data frame is a multi-usertransmission, wherein the data frame further comprises a high efficiencyWi-Fi Signaling Field 2 (HEW-SIG2), the HEW-SIG2 is adjacent to theHEW-SIGs in the data frame, the HEW-SIG2 comprises resource indicationinformation, the HEW-SIGs further comprises a HEW-SIG2 modulation andcoding scheme (HEW-SIG2 MCS) field, and the HEW-SIG2 MCS field indicatesa transmission modulation and coding scheme (MCS) of the HEW-SIG2; andparsing, by the station, the data frame to obtain the HEW-SIGs and theHEW-SIG2.
 6. The method according to claim 5, wherein the resourceindication information in the HEW-SIG2 comprises resource locations forcommunicating data by multiple users.
 7. The method according to claim6, further comprising: determining, by the station, resource locationsfor the station to use to communicate data according to the resourceindication information in the HEW-SIG2; and communicating, by thestation, the data at the resource locations for the station to use tocommunicate data.
 8. The method according to claim 5, wherein theHEW-SIGs further comprises a transition time field indicating adownlink-uplink transition time point.
 9. The method according to claim8, further comprising: determining, by the station, the downlink-uplinktransition time point according to a value of the transition time field,a time domain length of a resource unit, and an end time of thesignaling with reference to a preset formula, where the preset formulaincludes:Transition time point=Value of transition time field×Time domain lengthof the resource unit+End time of the next signaling.
 10. The methodaccording to claim 5, wherein the HEW-SIGs further comprises a HEW-SIG2length field and a duration field, wherein the HEW-SIG2 length fieldindicates a length of HEW-SIG2 signaling, and the duration fieldindicates a remaining duration of occupying a channel.
 11. An apparatus,comprising: a processor, configured to generate a data frame, whereinthe data frame includes a high efficiency Wi-Fi Signaling Field 1(HEW-SIG1), the HEW-SIGs comprises a frame structure indication field,and the frame structure indication field indicates a frame structure ofa scheduling transmission, wherein the frame structure of the schedulingtransmission comprises an uplink structure or a downlink structure, thescheduling transmission of the data frame is a multi-user transmission,the data frame further comprises a high efficiency Wi-Fi Signaling Field2 (HEW-SIG2), the HEW-SIG2 is adjacent to the HEW-SIGs in the dataframe, the HEW-SIG2 comprises resource indication information, theHEW-SIGs further comprises a HEW-SIG2 modulation and coding scheme(HEW-SIG2 MCS) field, and the HEW-SIG2 MCS field indicates atransmission modulation and coding scheme (MCS) of the HEW-SIG2; and atransmitter coupled to the processor, wherein the transmitter isconfigured to send the data frame.
 12. The apparatus according to claim11, wherein the resource indication information in the HEW-SIG2comprises resource locations for communicating data by multiple users.13. The apparatus according to claim 11, wherein the HEW-SIGs furthercomprises transition time field indicating a downlink-uplink transitiontime point, and a value M of the transition time field is:M=(T−End time of the HEW-SIG2)/Time domain length of each resource unitof the scheduling transmission; and wherein T is the downlink-uplinktransition time point.
 14. The apparatus according to claim 11, whereinthe HEW-SIGs further comprises: a HEW-SIG2 length field and a durationfield, wherein the HEW-SIG2 length field is indicates a length ofHEW-SIG2 signaling, and the duration field indicates a remainingduration of occupying a channel.
 15. An apparatus, comprising: areceiver, configured to receive a data frame, wherein the data frameincludes a high efficiency Wi-Fi Signaling Field 1 (HEW-SIG1), theHEW-SIGs comprises a frame structure indication field, the framestructure indication field indicates a frame structure of a schedulingtransmission, wherein the frame structure of the scheduling transmissioncomprises an uplink structure or a downlink structure, the schedulingtransmission of the data frame is a multi-user transmission, the dataframe further comprises a high efficiency Wi-Fi Signaling Field 2(HEW-SIG2), the HEW-SIG2 is adjacent to the HEW-SIGs in the data frame,the HEW-SIG2 comprises resource indication information, the HEW-SIGsfurther comprises a HEW-SIG2 modulation and coding scheme (HEW-SIG2 MCS)field, and the HEW-SIG2 MCS field indicates a transmission modulationand coding scheme (MCS) of the HEW-SIG2; and a processor coupled to thereceiver, wherein the processor is configured to parse the data frame toobtain the HEW-SIGs and the HEW-SIG2.
 16. The apparatus according toclaim 15, wherein the resource indication information in the HEW-SIG2comprises resource locations for communicating data by multiple users.17. The apparatus according to claim 16, wherein: the processor isfurther configured to: determine resource locations for communicatingdata by the apparatus according to the resource indication informationin the HEW-SIG2; and the receiver is further configured to communicatedata at the resource locations.
 18. The apparatus according to claim 15,wherein the HEW-SIGs further comprises a transition time fieldindicating a downlink-uplink transition time point.
 19. The apparatusaccording to claim 18, wherein the processor is further configured to:determine the downlink-uplink transition time point according to a valueof the transition time field, a time domain length of a resource unit,and an end time of the signaling with reference to a preset formula,where the preset formula includes:Transition time point=Value of transition time field×Time domain lengthof the resource unit+End time of the next signaling.
 20. The apparatusaccording to claim 15, wherein the HEW-SIGs further comprises: aHEW-SIG2 length field and a duration field, wherein the HEW-SIG2 lengthfield indicates a length of HEW-SIG2 signaling, and the duration fieldindicates a remaining duration of occupying a channel.